When will we reach herd immunity? Here are 3 reasons that’s a hard question to answer


Julie Leask, University of Sydney and James Wood, UNSWAs we try to control COVID-19, many people are keen to know what proportion of the population will need to be vaccinated in order to reach “herd immunity”.

It’s a reasonable question. People are asking because they want to know when we’ll see an end to lockdowns; when they’ll be able to reunite with loved ones overseas; when their businesses will have more security; when headlines will no longer be dominated by COVID-19.

Right now expert modellers are plugging in numbers and looking at various scenarios to estimate the scope of protection different levels of vaccination coverage will give us. We’re expecting to see the results of this modelling from the Doherty Institute as early as this week.

But it’s important to acknowledge it’s difficult to pin down a single magic number for herd immunity.

What is herd immunity again?

To understand why experts often avoid pinpointing a single vaccination figure needed to reach herd immunity for COVID-19, let’s first recap the concept.

Herd immunity is when immunity in a population is high enough to block the pathway for the ongoing transmission of the disease.

While vaccination provides each of us with direct protection against disease, with herd immunity, even people who are unvaccinated benefit from that blocked transmission pathway.

Different diseases have different thresholds for herd immunity. For measles, for example, the herd immunity threshold is 92%-94%. Estimates for COVID-19 have varied, with some putting it at 85% or higher.

However, many hesitate to give a single number. Here are three reasons why.




Read more:
What is herd immunity and how many people need to be vaccinated to protect a community?


1. Variations in the vaccines, and the disease itself

A single herd immunity figure is difficult to estimate when the infectiousness of SARS-CoV-2 (the virus that causes COVID-19) remains so variable.

We understand the infectiousness of a disease by looking at the R0, or reproduction number — the average number of people infected by one case where no control measures are in place. The ancestral strains of SARS-CoV-2 have an R0 of 2-3, but Delta is estimated to be twice as infectious, with an R0 around 4-6.

The type of vaccine, doses given (whether one or both), and how well the vaccines cover the different variants all factor in.

Estimates from the United Kingdom show two doses of the Pfizer vaccine are between 85% and 95% effective against symptomatic disease with the Alpha variant, while two doses of AstraZeneca are 70% to 85% effective. Overall vaccine effectiveness appears to drop about ten percentage points with the Delta variant.

The lower the vaccine effectiveness, the higher the level of coverage we’ll need to control COVID well.

2. We cannot cover the entire population yet

The Pfizer vaccine has now been provisionally approved for 12-15-year-olds in Australia. If it becomes routinely recommended for this age group, it will still take time to vaccinate them. Even once that occurs, there will remain a gap in our population protection among younger children.

Children should benefit somewhat from adult vaccination. In England, where overall vaccine uptake is 48.5% for two doses, there was initially a decline in infections for children aged under ten years. This is partly due to indirect protection offered by adults being vaccinated.




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How well do COVID vaccines work in the real world?


3. Population protection will vary in time and space

There is rarely a neat threshold after which everything changes for good. Vaccine protection in individuals is likely to wane over time. With that and new variants appearing, we will almost certainly need boosters to sustain population protection against COVID-19.

With influenza vaccination, we rarely even talk about herd immunity, because the duration of protection is so short. By the next flu season, immunity from the current season’s vaccine will be much less effective against the newest viral strain.

Spatially, protection can vary across localities and demographics. Even in a country that has reached a herd immunity threshold for vaccination coverage against measles, you can see small outbreaks in pockets of lower coverage in kids, or where a cohort of teens and adults weren’t adequately vaccinated as children.

The capacity to achieve herd immunity is also affected by population density and how much people in a population mix with a variety of others — what’s called heterogeneity of mixing.

A group of children playing a game of tug-of-war in a park.
We don’t yet have a COVID vaccine approved for children under 12.
Shutterstock

Life will gradually change as more people are vaccinated

Given these factors, it’s understandable experts often avoid giving a single figure for herd immunity.

With the infectiousness of Delta, we will need very high vaccination rates. Then, life will look different, particularly once this happens globally. Australia will be able to relax its border restrictions. We will likely see modified forms of quarantine, such as home quarantine, for those who are fully vaccinated.

COVID outbreaks will happen, but they will be less risky, with fewer people susceptible to serious illness. City or state-wide outbreaks will be replaced by more localised ones.

We will still require good public health measures like rapid contact tracing and isolation. Rapid tests may be used more often. New treatments may be found.




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All the while, we need to be as concerned about global vaccine coverage as we are about national coverage. Because all people, regardless of means, have a right to the freedoms and security that come from COVID-19 protection.

And as we’ve heard from global leaders, “None of us will be safe until everyone is safe”.The Conversation

Julie Leask, Professor, University of Sydney and James Wood, Public health academic, UNSW

This article is republished from The Conversation under a Creative Commons license. Read the original article.

A COVID ‘ring of steel’ around Sydney would play havoc with Australia’s supply chains


Claudio Divizia/Shutterstock

Flavio Romero Macau, Edith Cowan UniversityIf a “ring of steel” was actually placed around Sydney, as suggested by Victorian premier Daniel Andrews, the rest of Australia would suffer in ways that aren’t immediately apparent.

Completely sealing a city or a region is not unprecedented. It happened last year in China, India, Italy and France.

In those instances it wasn’t just local facilities that were shut down, but also factories and distribution centres serving the rest of the country and the movement of goods into and out of the regions.

The rest of Australia got a taste of what would happen earlier this month when Amazon temporarily closed down its Moorebank fulfilment centre in Sydney, after two workers tested positive to COVID-19. Suddenly, it was unable to ship tens of thousands of orders.

It’s worthwhile examining what a near-literal ring of steel would do.

Greater Sydney sold A$281 billion of goods and services to the rest of Australia in 2019/20 — $81 billion more than it brought in.

Made in Sydney

Sydney made five times as much from selling goods to the rest of Australia than it did from exports.

While financial services accounts for most of these sales (42.5%), manufacturing comes in a respectable second (12.6%).

Smithfield-Wetherill Park Industrial Estate.

Sydney’s Smithfield-Wetherill Park Industrial Estate, home to more than 3,000 manufacturing, wholesale, and transport firms using more than three million square metres of warehouse space, is one the largest industrial areas in the Southern Hemisphere.

About 8% of Australia’s poultry meat and 15% of Australia’s mushrooms come from Sydney. Bacon, ham, and salami would also take a hit without the Primo Foods facility in Chullora.

Without Asahi Beverages in Huntingwood and Coca Cola Amatil’s Eastern Creek distribution centre and Northmead bottling plant, Australia would find it hard to get Pepsi, Coke and Schweppes soft drinks.

Petrol would become harder to come by. While Sydney’s Clyde and Kurnell refineries closed early last decade, Sydney remains a major hub for imports. Sydney’s Clyde and Parramatta terminals store gasoline, diesel and lubricants.




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Much of Australia’s manufacturing takes place in Greater Sydney, including boilers and specialised equipment for the mining industry.

Toilet paper would at least be safe. Australia has four main manufacturers, three in Victoria (Sorbent, Safe, Merino) and one in South East South Australia (Kleenex).

Arnotts has moved much of its output to Brisbane, making Tim Tams safe as well.

Going through Sydney

Port Botany: 2.5 million containers per year.
National Maritime Museum

Greater Sydney is Australia’s largest logistics hub. Sydney’s Kingsford Smith Airport handles 45% of Australia’s air freight.

Of the 2.5 million containers arriving in Port Botany each year, one-fifth are moved to the rest of Australia over roads such as the Hume and Pacific highways, or through trains running between Sydney and Melbourne, Brisbane and Perth.

Australia Post processes more than half a million parcels a day at Chullora.

The Woolworths distribution facilities at Yennora and Minchinbury move nine million cartons a week.

Many of Australia’s distribution chains aren’t set up to operate without Sydney.

Depending on its strength, a ring of steel would impose considerable challenges.The Conversation

Flavio Romero Macau, Associate dean, Edith Cowan University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

How a perfect storm of events is turning Myanmar into a ‘super-spreader’ COVID state


Adam Simpson, University of South Australia and Nicholas Farrelly, University of TasmaniaMyanmar is facing a catastrophic health crisis that could have ramifications not just for the country’s long-suffering people, but across the region as well.

The country is experiencing a major spike in COVID cases — what one Doctors Without Borders official referred to as “uncontrolled community spread” — fuelled by the military junta’s gross mismanagement of the crisis and a collapsing health sector.

The military regime’s official COVID statistics are running at around 6,000 cases and 300 deaths per day, but no one believes these are accurate. This is, after all, the junta that staged a military coup in February and then tried to argue it was constitutionally valid.

With only 2.8% of Myanmar’s 54 million people fully vaccinated, there are now concerns the country could become a “COVID superspreader state”. And this could lead to the emergence of new variants, says the UN’s special rapporteur for human rights in Myanmar.

This is very, very dangerous for all kinds of reasons […] This is a region that is susceptible to even greater suffering as a result of Myanmar becoming a super-spreader state.

Doctors being imprisoned

The UN says a “perfect storm” of factors is fuelling the deepening health crisis.

Medical staff have been on strike as part of the civil disobedience movement against the coup. Oxygen and other medical equipment are increasingly expensive and in short supply. Even getting an oxygen concentrator into Myanmar is not straightforward, though Singapore said this week it will rush 200 machines into the country.




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Most troublingly, at least 157 medics, including the former head of Myanmar’s COVID-19 vaccination program, have been arrested and charged with high treason. In Yangon, military personnel have pretended to be COVID patients in need of emergency treatment, then arrested the doctors who came to help.

Reliable figures on the infection rate are impossible to obtain, but civil society groups that assist with cremations and funeral services in Yangon say they are seeing up to 1,000 uncounted COVID deaths a day in that city alone. The national total may be several thousand per day.

One reason it’s impossible to get an accurate count of COVID cases is the extremely low rate of testing. There are only around 15,000 COVID tests being conducted per day in a country of 54 million people. The tests are, however, returning a positive rate of around 37%, or 370 positives for every 1,000 tests.

It’s also believed nearly 50 prisoners at the crowded, notorious Insein Prison are now infected with COVID but are being denied treatment by the military.

These prisoners include top leaders from Aung San Suu Kyi’s National League for Democracy, doctors connected with the civil disobedience movement, and foreigners like Australian academic Sean Turnell, an adviser to Suu Kyi who was arrested by the junta after the coup and is being held on bogus charges.

Another adviser and lawyer to Suu Kyi, Nyan Win, died last week after being infected with COVID at Insein.

Protesters marching against the junta in the capital, Yangon, in mid-July.
AP

Myanmar’s poor are disproportionatly suffering

Such a catastrophic health situation is exacerbating Myanmar’s inequalities. Poorer people are less able to socially distance and less likely to get tested and receive meaningful treatment. They suffer invisibly, often in silence.

In a report published this week, the World Bank estimated Myanmar’s economy would contract by 18% this year due to the effects of the pandemic and the coup. The share of people living in poverty is also likely to more than double by the beginning of 2022, compared to 2019.




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We know how to cut off the financial valve to Myanmar’s military. The world just needs the resolve to act


The ethnic minority regions of the country may well be disproportionately suffering, too. Since the coup, conflicts have intensified across the country between the military and the ethnic armed organisations and pro-democracy advocates that have joined them, causing immense social dislocation.

The UN refugee agency estimates 200,000 people were internally displaced from February to June, bringing the total of displaced people in the country to 680,000. These marginalised groups are even less likely to have access to medical treatment.

These figures are also not taking into account the refugees outside the country, such as the million Rohingya languishing in the cramped refugee camps in Bangladesh. The Bangladesh government has said it will begin vaccinating the Rohingya next month.

International aid desperately needed

When Cyclone Nargis killed 140,000 people in Myanmar in 2008, the country’s previous military regime received wide-ranging offers of assistance from ASEAN, the regional bloc, and the wider international community.

But since the coup, Western aid to Myanmar has been redirected through non-government groups, causing hold-ups. The UN says the junta has also yet to account for US$350 million in COVID aid the International Monetary Fund sent to Myanmar just days before the coup in February.

The country hasn’t received vaccine doses since May, though China pledged to send 6 million doses by August, with the first batch arriving last week. China may end up being the most proactive donor, since it is worried about a COVID outbreak along its shared border with Myanmar.

Optimists say this may be a time for reconciliation and for everyone in Myanmar to unite against the common enemy of COVID. Yet it is hard to imagine that happening right now, when the military’s own mishandling of the pandemic has generated so much outrage from the population.




Read more:
Sanctions against Myanmar’s junta have been tried before. Can they work this time?


What can be done? Perhaps Australia, which we are told is “awash” in AstraZeneca vaccines, could make rapid moves to send desperately needed supplies to Myanmar via its non-government partners. It would be a bold and impressive diplomatic move.

There is then the need for the international community to confront the Myanmar generals for their appalling mishandling of the country since the coup. By seizing control from elected leaders, they have impoverished their own people, sparked new conflicts and exacerbated the damage done by a global pandemic.

The heartbreaking reality is the people of Myanmar have been left without the prospect of significant relief at the worst possible time.The Conversation

Adam Simpson, Senior Lecturer, University of South Australia and Nicholas Farrelly, Professor and Head of Social Sciences, University of Tasmania

This article is republished from The Conversation under a Creative Commons license. Read the original article.

India’s vaccine rollout is ignoring the many inequities in its society


Rajib Dasgupta, Jawaharlal Nehru University Some 6 months after India began what is said to be the largest COVID-19 vaccination drive in the world, equitable distribution has been a challenge.

A recent instance from a remote area in one of India’s hill states is illustrative. According to news reports, over 90% of vaccination slots meant for locals were booked by people from other areas.

Residents lost out because the area had no internet connectivity. To address the digital divide, local authorities had to appeal to the outsiders to cancel their bookings.

This access issue is just one of many ways India’s prioritisation strategy for COVID-19 vaccination has fallen short.




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Who gets the shot first: what did experts agree on?

The World Health Organization (WHO) had foreseen vaccine shortages and consequently, inequitable distribution. In 2020, it advocated a nuanced approach to ensure those who most needed the vaccine got it.

The WHO’s Strategic Advisory Group of Experts on Immunization (SAGE) designed a document called the “Values Framework”. This document listed over 20 vulnerable groups such as homeless peoples, those living in informal settlements, and those in urban slums.

They underscored that countries ensure access to priority populations and take action to ensure equal access to everyone who qualifies under a priority group, particularly socially disadvantaged populations.

How did India prioritise vaccines?

The first phase of India’s rollout began in January, covering an estimated 30 million healthcare and front-line workers.

On March 1, the second phase began which incorporated people over 45 with chronic illnesses, and the over-60s. On April 1, this was expanded to everyone over 45.




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From May 1, it was decided all adults over 18 would be included.

Now, despite all adults being eligible, only 10% are fully protected with two doses. Despite the overall pace of vaccination increasing, the target of 135 million doses administered in July may be missed, and things look unlikely to improve in August.

With the threat of a third wave fuelled by variants, relaxing of lockdown restrictions, and the constant uptick in cases in two of the larger Indian states (Kerala and Maharashtra) as well as most of the North Eastern states, there’s an urgent need to increase vaccine coverage.

How should India prioritise vaccines?

India’s prioritisation strategy was limited to age, and to front-line workers specifically linked to COVID management — police and armed forces personnel, disaster management volunteers and municipal workers. It did not address the real-world diverse spectrum of vulnerabilities.




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Why couldn’t India’s health system cope during the second wave? Years of bad health policies


The Values Framework points to a range of vulnerabilities and priorities and includes people unable to physically distance such as those in geographically remote and clustered populations (detention facilities, dormitories, refugee camps and dense urban neighbourhoods).

Levels of COVID-19 among prison populations and high levels of antibodies (suggesting prior infection) among slum residents shows this is a legitimate concern.

Then there are those who are at high risk of transmitting infection such as youth who are mobile but largely asymptomatic, and school-going children. Vaccinating them early would minimise disruption of their education and socio-emotional development. The union health minister has announced vaccination of children is likely to begin in August.

Workers in non-essential but economically critical sectors, particularly in occupations that do not permit remote work such as construction and food services, should also be vaccinated early.




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How can the world help India — and where does that help need to go?


While only health workers were included in the category of essential workers, teachers, childcare providers, agriculture and food workers, and transport workers should have been added to this category.

Finally, to ensure equity, the needs of those who, at no fault of their own, are at risk of experiencing greater burdens from the COVID-19 pandemic, must be addressed.

This would include those living in extreme poverty, low-income migrant workers, nomadic populations, refugees or internally displaced persons, populations in conflict settings, those affected by humanitarian emergencies, and hard-to-reach groups.

At least one Indian state — Chhattisgarh — tried to reach out to its poorest, by proposing those under the state’s food scheme be vaccinated first in the 18–44 years category. However, after the intervention of the courts, the state had to reverse the order and allow vaccination for all adults.

What’s the fallout?

Rural-urban and gender inequities in the vaccine rollout have emerged as significant concerns.

By late May, 114 of India’s least developed districts had administered just 23 million doses to its 176 million residents. India’s nine major cities received the same number of doses, despite having half as many people.

During the same period, 17% more men were immunised than women.

Equity groups need to be given priority access to vaccinations to ensure those already more vulnerable to death, disease and destitution, and least likely to be able to seek treatment due to poverty, distance, or other social disadvantages, are protected.The Conversation

Rajib Dasgupta, Chairperson, Centre of Social Medicine and Community Health, Jawaharlal Nehru University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Vaccination rate needs to hit 70% to trigger easing of restrictions


Michelle Grattan, University of CanberraSeven in ten people aged 16 and over will need to be fully vaccinated for COVID restrictions to begin to be eased, under targets agreed in principle by national cabinet on Friday.

Further relaxation and opening beyond that, including a near end to lockdowns, will require 80% of those eligible to have had two doses.

At present the proportion of people 16 and over fully vaccinated is 18.24%, while nearly 40% have had a single dose.

Each targets is dual – it must be met at both the national level and in the particular state or territory. Scott Morrison described it as a “two key process”.

Announcing the targets on Friday night, Morrison said no timeline has been attached to them.

But he believed the 70% target could be reached by the end of the year.

“There will certainly be the supply and the distribution and the opportunity to do that. But whether that is achieved is up to all of us.”

The long-awaited numbers have been attached to the four-phase re-opening plan previously endorsed in principle by the national cabinet.

In the current phase, the objective is to suppress COVID, including by tough lockdowns.

The second “transition” phase, triggered by the 70% vaccination levels, seeks to minimise severe illness, hospitalisation and deaths with low level restrictions.

In this phase, lockdowns would still be possible but less likely.

Restrictions would be eased on vaccinated residents. Morrison said this was “because if you’re vaccinated, you present less of a public health risk.

“You are less likely to get the virus. You are less likely to transmit it.” But the detail of how this would operate is still to be worked out.

The third “consolidation” phase – triggered by the 80% threshold – would have only highly targeted lockdowns, such as for vulnerable communities, and would exempt vaccinated residents from all domestic restrictions.

In the final phase, COVID would be treated like other infectious diseases.

The targets follow modelling from the Doherty Institute and work by Treasury.

They come as the latest tally of cases in Sydney, where the lockdown has been extended by one month, was 170 new community cases.

Amid calls for the NSW government to impose an even tougher lockdown, Morrison said it had been agreed “under this plan, no state or territory is required to increase the restrictions beyond where they are right now.”

Morrison said in the suppression phase, “going
hard early” with lockdowns “ultimately results in less cost on the economy”.

But in phase B “then the calculus does change and lockdowns do cost a lot”.

After the announcement crossbench MP Craig Kelly, who was formerly in the Liberal party, lashed out on Twitter, claiming constitutional freedoms were being violated and declaring “WE MUST FIGHT THIS”. The Conversation

Michelle Grattan, Professorial Fellow, University of Canberra

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Australia shouldn’t ‘open up’ before we vaccinate at least 80% of the population. Here’s why


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Stephen Duckett, Grattan Institute and Will Mackey, Grattan InstituteEarlier this month National Cabinet released a four-phase COVID response plan. It wasn’t so much a plan – it had no dates and no thresholds – but more a back-of-the-napkin thought bubble. It was sensible, but vague.

National Cabinet now faces the hard task of converting vagueness into a real plan. To do this it must answer the question: what proportion of the Australian population needs to be vaccinated before we can open our international borders?

This means allowing stranded Australians to return, letting footloose people travel overseas, and welcoming international tourists and students again.




Read more:
Australia has a new four-phase plan for a return to normality. Here’s what we know so far


Well qualified experts differ on the requisite threshold for vaccination partly because there are so many unknowns, such as how quickly the Delta variant of COVID would spread through Australia if we open up, and how effective the different vaccines will prove to be in preventing transmission.

But new Grattan Institute modelling shows it would be dangerous for Australia to open up before at least 80% of the population is vaccinated.

Here’s what we found, and how we came to the 80% figure. Let’s start with the good news.

Vaccines offer substantial protection

Both vaccines on offer in Australia – Pfizer and AstraZeneca – are effective at preventing infections from the Delta strain. Two doses of Pfizer offers about 88% protection against infection, while two doses of AstraZeneca offers about 67% protection.

Vaccinated people can still catch COVID, but those that do pass it on to about half as many others compared to the unvaccinated.




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Evidence from the United Kingdom, Canada, and the European Union – areas with higher vaccination levels than Australia – also suggests both vaccines offer substantial protection against hospitalisation and death from COVID. A vaccinated person is about 95% less likely than an unvaccinated person to end up in hospital with COVID.

Now for the bad news.

The delta strain is far more infectious

Researchers estimate the Delta variant is 50% to 100% more infectious than the Alpha variant, which itself was more transmissible than the variant that was dominant throughout 2020.

The effective reproduction number, or Reff, tells us how many people one infected person will spread the virus to, taking into account behaviour and public health measures in place designed to reduce transmission, such as masks and physical distancing.

A masked supermarket check out operator scans products.
The Reff changes according to the public health measures in place, such as mask mandates.
Shutterstock

If the Reff of the Delta variant in Australia is around 6 without vaccination, having 50% vaccination coverage will reduce the Reff to 3.

But the national goal must be to bring the Reff down to below 1, which would mean each person who was infected would infect less than one other person – and the virus would eventually peter out.

The higher the vaccination rate, the lower the effective reproduction number. Each person vaccinated offers a chance of breaking a chain of transmission that might lead to an outbreak.

Not only are vaccinated people less likely to become infected, they are also less likely to pass the virus onto others if they are.

The higher the vaccination rate, the lower the effective reproduction number

Effective reproduction number (Reff) by population vaccination rate.
Grattan Institute

So why do we need 80% of people vaccinated?

Grattan Institute’s model simulates the spread of COVID within a partially vaccinated population, and helps us peek into the future.

It uses age-based hospitalisation and intensive care unit (ICU) admission rates from more than a year of COVID data from Australian ICU units. It also assumes children under 16 are about one-fifth less likely to get COVID, and children over the age of two are able to be vaccinated.

In most of our simulations, older people have higher rates of vaccination, and no age group has more than 95% vaccine coverage.




Read more:
When will we reach herd immunity? Here are 3 reasons that’s a hard question to answer


We ran thousands of simulations of different vaccination rates, and different estimates of the Reff. The outcomes for 12 distinct scenarios are shown in the table below.

You can see why we recommend Australia not open up until at least 80% of the population is vaccinated – it is the only scenario where the virus is managed, with hospitalisations and deaths kept down to reasonable levels, even if the Reff is high.



Let’s break it down

Our simulations show that opening up at 50% vaccination rate (scenario 1) is a very bad idea, with many, many thousands of deaths.

Scenarios 2 and 3 are the optimist’s and gambler’s scenarios. If you are lucky and the Reff of Delta in Australia is 4 (with 70% vaccination rate) or 5 (with 75% vaccination rate), deaths and hospitalisations would not rise above moderate levels, and lockdowns could end and the borders could reopen.

But if you gambled on the wrong Reff, our hospitals would be overwhelmed and deaths would be unacceptably high. Opening the borders is a one-shot gamble: if you make the wrong call, the virus will quickly spread and all the good work and hard yards of living through lock-downs over the previous two years will have been wasted.

Public health decision-making is often risk averse, for the best of reasons. The difference in virus spread, hospitalisations and deaths between opening at 75% and at 80% are big, but the wait between the two thresholds may only be a month or two.
This is why we recommend an 80% vaccination rate (scenario 4) as the threshold for opening up.

Even if the Reff of Delta is 6, our hospital system will not be overwhelmed, and deaths will not rise above the number of deaths in a moderate flu season, such as 2010, when there were 2,364 flu deaths.




Read more:
80% vaccination won’t get us herd immunity, but it could mean safely opening international borders


The Conversation


Stephen Duckett, Director, Health Program, Grattan Institute and Will Mackey, Senior Associate, Grattan Institute

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Over 18 and considering the AstraZeneca vaccine? This may help you decide


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Natasha Yates, Bond UniversityIf you are 18 or older, and in an area where there is a COVID-19 outbreak, the best vaccine for you is the one you can get right now. That possibly means you should get the AstraZeneca vaccine, as Pfizer is still in short supply.

This updated advice was given by ATAGI (the Australian Technical Advisory Group on Immunisation), the government’s expert vaccine advisory body, on July 24. Why would it change to recommending either AstraZeneca or Pfizer, after months of preferring Pfizer for younger people?

More young people are being hospitalised, in ICU and dying during this current outbreak in Australia, where the Delta strain is dominating.

Whether this is a function of the Delta strain being more dangerous to young people, or because older people are (as a group) more likely to be protected by already being vaccinated, remains a subject of debate.




Read more:
Why is Delta such a worry? It’s more infectious, probably causes more severe disease, and challenges our vaccines


There is little argument, however, that the Delta strain is more infectious, which is why we want to vaccinate our population as quickly as possible.

So if you are 18 or older and have not been vaccinated yet, you may be asking whether getting an AstraZeneca vaccine right now is the right thing for you to do. To answer this we need to consider the benefits and risks of the AstraZeneca vaccination.

What do vaccines achieve?

When thinking about what any COVID-19 vaccine should achieve, there is an order of priority.

First, it should stop people who catch COVID-19 from dying.

Second, it should reduce risk of severe disease (symptoms bad enough to need ICU treatment).

Third, hospitalisations should go down.

Woman in a mask at a supermarket looks at her smartphone.
Vaccines need to protect people from death and severe disease.
Shutterstock

If a vaccine is doing more than these three things, it is a bonus.

We are very lucky the AstraZeneca and Pfizer vaccines not only achieve all three, they also decrease numbers of people suffering illness of any sort (including mild symptoms), and possibly even reduce transmission (making people who have caught COVID-19 less infective).

Do vaccines work against the Delta variant?

Since Delta became the dominant strain of COVID-19 worldwide, researchers have been working hard to see how well current vaccines perform against it.

So far, the news is good. Let’s look at the evidence.

In the United Kingdom where the Delta strain is the cause of the majority of infections at the moment, there were 229,218 COVID infections between February and July. Of these, 12.5% were in fully vaccinated people. These are known as “breakthrough infections” (because they “broke through” the protection of the vaccine).

Of those breakthrough infections, 3.8%, required a visit to ED. Just 2.9% required hospital admission, and less than 1% died.

This means even though the vaccines didn’t fully protect people against disease, they did achieve their primary purpose: to save lives and keep people out of hospital.




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Most COVID deaths in England now are in the vaccinated – here’s why that shouldn’t alarm you


Another study in the UK that narrowed down to look at just hospitalisation with Delta strain concludes AstraZeneca is 92% effective against hospitalisation, after two doses.

Other studies have shown a 60% to 67% reduction in symptomatic disease.

Although AstraZeneca works to reduce infectivity of the Delta strain, vaccinated people can still transmit it to others.

That’s why it’s so important for vaccinated people to still observe all the other evidence-based ways of reducing spread including wearing masks, social distancing, and lockdown restrictions – at least until we have enough people in the community vaccinated.




Read more:
When will we reach herd immunity? Here are 3 reasons that’s a hard question to answer


But what are the down sides?

Of course there are potential risks from the AstraZeneca vaccine: injection site pain, tiredness, headache, muscle pain, fever and chills are the most commonly reported side effects.

Most of these are mild and temporary, going away within one to two days.

Man in a home office takes his glasses off and rubs his eyes.
Most symptoms are mild and resolve quickly.
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There are also rare but severe side effects: anaphylaxis (two to five per million people), and thrombosis with thrombocytopenia (TTS) – known colloquially as “clots”. The only risk factor that has been shown to predict how likely you are to get TTS after an AstraZeneca vaccine is age.

TTS clots are very different from other blood clots you may hear about. In the same way that having a basal cell cancer removed from your skin does not make you more at risk of getting a brain tumour, having a blood clot in your medical history (or family history) does not make you more at risk of TTS.

In addition, we have effective treatments for TTS now, so the death rate is low.

To keep it in perspective, your risk of getting a blood clot from TTS is still far less than your risk of dying in a car accident in the next year, and most people still don’t think twice about getting into a car.




Read more:
How rare are blood clots after the AstraZeneca vaccine? What should you look out for? And how are they treated?


Obviously, if there is no COVID-19 in the community then the risk from the vaccine will outweigh the risk from the disease – even a tiny risk is bigger than zero.

The reason ATAGI changed its advice to recommend the AstraZeneca vaccine to younger age groups in areas of outbreak is because as soon as COVID-19 starts to spread in the community, the risk of serious disease and death skyrockets. Which makes the vaccine suddenly become a very sensible option in Sydney and other high-risk areas.

How can you get it?

If and when you decide to have the AstraZeneca vaccine and you live in NSW, you can simply book in with any place that is giving it in your area. This may be a GP or state vaccination clinic.

You are not required to see a GP first, but of course you should only book once you’ve had your questions answered and are ready to go ahead with it.

Apart from contacting local providers directly, you can register for vaccination via the eligibility checker here (you fill in your details after completing the checker).

Pharmacies will not be administering AstraZeneca vaccines to people under 40 at this stage.

Young man on a train looks at his phone.
You can register for a vaccination online.
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Finally, I have had in my practice many young people express frustration at being unable to get a vaccine before now, because they see it as a vital step forward for our community and the world.

Their lives have often been hugely disrupted by COVID-19 and they believe the risk of any vaccine is better than continuing with the status quo.

As one patient told me: “I’m young, I live a risky life. Getting this vaccine is the safest thing I have done all week.”The Conversation

Natasha Yates, Assistant Professor, General Practice, Bond University

This article is republished from The Conversation under a Creative Commons license. Read the original article.