The Pfizer vaccine may not be the best choice for frail people, but it’s too early to make firm conclusions


Nathan Bartlett, University of Newcastle

Reports of about 30 deaths among elderly nursing home residents who received the Pfizer vaccine have made international headlines.

With Australia’s Therapeutic Goods Administration (TGA) expected to approve the vaccine imminently and the roll out set to begin next month, this development might seem like cause for concern around the safety of the vaccine.

But there are a few reasons it shouldn’t be.




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What we know

We haven’t seen this issue reported in any other countries which are rolling out the Pfizer vaccine.

Norway has reported about 45,000 people around the country have been vaccinated against COVID-19 so far. Their vaccine program has mostly focused on residents in nursing homes.

In other countries, there may be more of a focus on frontline health-care workers in the first instance. So if there is any association between deaths in the elderly and this vaccine, it may not be apparent as yet.

It also depends on surveillance. Norway may have an especially rapid surveillance and reporting system in place, efficiently tracking everyone who has been vaccinated and quickly reporting any adverse outcomes.

We would expect surveillance reporting from other countries with an active vaccination program soon, increasing data critical to building a more accurate picture of vaccine safety across different populations.

Norway’s reports will sensitise other countries to monitoring vaccine recipients closely, particularly those in nursing homes who are older and vulnerable. We may see further reports on this coming through in coming weeks from other countries.

But we also may not. We have limited information regarding these cases in Norway. The people reported to have died were elderly and very frail. Many had significant underlying health conditions common in the very old, and may have been nearing the end of their lives independent of the vaccine.

Though they are under investigation, it’s important to note the deaths have not been linked conclusively to complications from the vaccine. Meanwhile, Australian experts have called for calm.

Vaccines and the elderly

In the recent history of vaccines, we haven’t seen any trends showing deaths in elderly people following vaccination. For example, there’s no evidence the annual influenza vaccine has been associated with deaths in older people — or people of any age.

It’s important to note though, that in making a comparison with the flu shot or another vaccine and the Pfizer vaccine for COVID-19, we’re comparing apples and oranges.

The Pfizer vaccine is based on mRNA technology, which is completely new in a human vaccine. This technology introduces part of the genetic material of the SARS-CoV-2 virus in the form of messenger RNA (mRNA). This instructs your cells to make part of the virus which stimulates an immune response that inhibits infection and protects against disease.

All vaccines are designed to generate an immune response — albeit in different ways — to prepare our bodies to fight the virus if and when we encounter it.

A nurse administers a vaccine to an elderly lady wearing a mask.
With any vaccine, different people will experience side effects differently.
Shutterstock

Creating an immune response leads to inflammation in the body. Some people will experience no side effects from a vaccine, but the inflammation can manifest in different ways in different people and between different vaccines. This may mean a reaction at the site of the injection, or fatigue, or feeling unwell.

The deaths in Norway were reportedly associated with fever, nausea and diarrhoea, which, while at the severe end of the spectrum of vaccine side effects, would be tolerable for the vast majority of people.

How different people will respond to the mRNA is what we’re starting to understand now. It’s possible this vaccine will have more serious effects in older, vulnerable people where the initial inflammatory response could be overwhelming.

But it’s still too early to draw any conclusions.




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Side effects show a vaccine is generating an immune response

Vaccines need to generate an immune response in order to work, and side effects are a byproduct of our bodies mounting an immune response.

While the deaths are sad, they shouldn’t be cause for alarm. This actually tells us the vaccine is stimulating an immune response. For most people that response will be entirely tolerable and lead to development of immune memory that protects you from severe COVID-19.

The big challenge for any vaccine is generating enough of an immune response so you’re protected from the disease in question, but not too much that you experience serious adverse effects. Where this line in the sand exists will vary across different people, but the oldest and frailest vaccine recipients are likely to be most at risk of severe, potentially life-threatening reactions.

So for those who may be more susceptible, we may want to be a little more cautious. In approving the Pfizer vaccine, the TGA may consider advising against this particular vaccine for people who are very elderly and frail, particularly those who have other conditions and are potentially nearing the end of their lives.

Ideally, the vaccine should be considered on a case-by-case basis for this group, carefully weighing up the risks and benefits in each situation, based on the best available data.




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The Conversation


Nathan Bartlett, Associate Professor, School of Biomedical Sciences and Pharmacy, University of Newcastle

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

Think you’re allergic to penicillin? There’s a good chance you’re wrong



File 20190411 2914 mksw66.jpg?ixlib=rb 1.1
A rash people assume is a reaction to penicillin may not be related to the drug at all.
From shutterstock.com

Greg Kyle, Queensland University of Technology

Are you allergic to penicillin? Perhaps you have a friend or relative who is? With about one in ten people reporting a penicillin allergy, that’s not altogether surprising.

Penicillin is the most commonly reported drug allergy. But the key word here is “reported”. Only about 20% of this 10% have a true penicillin allergy – so the figure would be one in 50 rather than one in ten.

People may experience symptoms they think are a result of taking penicillin, but are actually unrelated. If these symptoms are not investigated, they continue with the belief that they should steer clear of penicillin.




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This can become a problem if a person is sick and needs to be treated with penicillin. Penicillin and related antibiotics are the most common group of drugs used to treat a broad range of infections, from chest or throat, to urinary tract, to skin and soft tissue infections.

The overestimation of penicillin allergies is also not ideal because it means people are being treated with a broader range of antibiotics than necessary, which contributes to the problem of antibiotic resistance.

Yes, penicillin comes from mould

To understand more about why so many people think they’re allergic to penicillin, we need to look at a brief history of the drug.

Penicillin (benzylpenicillin or Penicillin G) was first discovered in 1928 and first used in 1941.

It was grown from a mould, as it is today. The liquid nutrient broth the mould grew in was drained, and the penicillin purified from it.

In the 1930s and 40s, and even through the 1960s and 70s, purification techniques were not as efficient as they are today. So, many early allergic reactions are thought to be due to impurities in the early penicillin products – especially injections.

Penicillin is now more versatile and can kill a wider range of bacteria than in its earlier days.
From shutterstock.com

Penicillin and the range of antibiotic compounds that followed it revolutionised how we treat bacterial infections.

This led to widespread, and sometimes inappropriate, use of these medicines. Antibiotics do not work against viruses, but are sometimes prescribed for bacterial infections that occur while people have viral infections such as glandular fever.

We know using penicillin while a person has glandular fever can cause a rash that looks like penicillin allergy but is not related.

People may report symptoms to their health professionals that seem like a reaction to penicillin. Perhaps these symptoms are not fully investigated because it takes time and can be expensive – they’re just put down to the common penicillin allergy.

Further, some people perceive other side effects of a penicillin antibiotic such as nausea or diarrhoea as an allergy, when these are not, in fact, allergy symptoms.

From this point, the penicillin family will not be used to treat these patients.




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The problem of antibiotic resistance

An allergy to penicillin can also limit the use of some other antibiotics which may cross-react with the allergy.

Cross reaction occurs when the chemical structure of another antibiotic is so similar to the structure of penicillin that the immune system gets confused and recognises it as the same thing.

To avoid this, doctors need to look to antibiotics from other medication classes when prescribing patients with a documented penicillin allergy.

But we need to be careful when drawing on a wider range of antibiotics. This is because the more bacteria are exposed to antibiotics, the more likely they are to develop resistance to these antibiotics.

The range of penicillins we have today came from experimenting with the chemistry of the original penicillin molecule and changing its properties.
From shutterstock.com

To address the growing problem of antibiotic resistance, we now try to restrict antibiotics as much as possible to the lowest level one that will kill the specific bacteria.

We don’t kill tiny ants in our gardens with a sledgehammer, so likewise, we use a narrow-spectrum antibiotic wherever possible to keep the broad-spectrum antibiotics for severe and complex infections.

The penicillin family contains both narrow and broad-spectrum antibiotics. Ruling out this family and its “cousins” when we don’t need to can limit the choice of antibiotics and increase the chance of making other antibiotics less useful.

Can I get tested?

Studies show penicillin allergy reduces over time. So even if you did have a true penicillin allergy, it may have gone away over several years.

Under the guidance of your doctor, it is possible to be tested to see if you’re allergic – or still allergic – to penicillin.

A skin “scratch” test involves injecting a small amount of penicillin and monitoring for a reaction. Rescue medications will be on hand in case you do have a severe reaction. Your GP will probably refer you to an allergy specialist to get this done.




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If you have been told you’re allergic, you should first try to find out when the reaction occurred and what happened in as much detail as possible.

Let your GP know all this information and he or she can then decide whether a skin test might be appropriate.

Do not try a test dose at home – the risk of a life-threatening reaction is not worth it.

And if you believe you are allergic to penicillin, the most important thing to do is tell each health professional (doctor, pharmacist, nurse, dentist, etc.) you come into contact with.The Conversation

Greg Kyle, Professor of Pharmacy, Queensland University of Technology

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