What we know and don’t know about Pfizer vaccine deaths in Norway

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

With Australia’s Therapeutic Goods Administration (TGA) set to approve the vaccine soon and with deployment to begin next month, this development could appear to be a cause for concern about the safety of the vaccine.

But there are several reasons why it shouldn’t be.

What we know

We have not seen this problem reported in any other country that deploys the Pfizer vaccine.

Norway has reported that around 45,000 people across the country have been vaccinated against COVID-19 so far. Their vaccination program has mainly focused on residents of nursing homes.

In other countries, the focus may be more on frontline health workers. So if there is an association between elderly deaths and this vaccine, it may not yet be apparent.

It also depends on monitoring. Norway may have a particularly rapid surveillance and reporting system, making it possible to effectively track all those vaccinated and promptly report any adverse reactions.

We would expect surveillance reports from other countries with an active immunization program to be available soon, increasing the data essential to build a more accurate picture of vaccine safety in different populations.

Norway’s reports will sensitize other countries to close surveillance of those vaccinated, particularly those in nursing homes who are older and vulnerable. We may see more reports on this topic from other countries in the coming weeks.

But neither can we. We have limited information on these cases in Norway. The people who would have died were elderly and very fragile. Many had significant underlying health problems common in very old people, and may have approached the end of their lives regardless of the vaccine.

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

Vaccines and the elderly

In the recent history of vaccines, we have not observed any trend showing deaths in the elderly after vaccination. For example, there is no evidence that the annual flu shot has been linked to deaths in the elderly – or of any age.

It is important to note however that by comparing with the flu vaccine or another vaccine and Pfizer’s COVID-19 vaccine, we are 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 asks your cells to be 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 off the virus if and when we encounter it.

The creation of an immune response leads to inflammation in the body. Some people will not experience any side effects from a vaccine, but inflammation may show up in different ways in different people and between different vaccines. It may mean a reaction at the injection site, fatigue, or feeling unwell.

Deaths in Norway have reportedly been associated with fever, nausea and diarrhea, which, although on the severe end of the vaccine side-effect spectrum, would be tolerable for the vast majority of people.

We are now starting to understand how different people will react to mRNA. This vaccine may have more serious effects in the elderly and vulnerable, where the initial inflammatory response could be overwhelming.

But it is still too early to draw any conclusions.

Side effects show a vaccine generates an immune response

Vaccines must generate an immune response to work, and side effects are a byproduct of our bodies developing an immune response.

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

The big challenge for any vaccine is to generate enough immune response that you are protected from the disease in question, but not so that you experience serious side effects. Where this line in the sand exists will vary from person to person, but the oldest and most fragile vaccinees are likely to be most at risk of serious, potentially fatal reactions.

So for those who may be more sensitive, we might want to be a little more careful. In approving the Pfizer vaccine, the TGA may consider advising against this particular vaccine for the very old and frail, especially those who have other conditions and who are potentially at the end of their life.

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

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.