Reports of about 30 deaths among residents of elderly nursing homes who received the Pfizer vaccine have made international headlines.
As the Australian Therapeutic Goods Administration (TGA) is expected to approve the vaccine in the short term and rollout will begin next month, this development appears to be a cause for concern about the vaccine’s safety.
But there are a few reasons why this shouldn’t be.
What we know
We have not reported this issue in other countries introducing the Pfizer vaccine.
Norway has reported that around 45,000 people across the country have been vaccinated against COVID-19 so far. Their vaccine program was primarily aimed at residents in nursing homes.
In other countries there may initially be more attention to primary health care workers. So if there is a link between deaths in the elderly and this vaccine, it may not be clear yet.
It also depends on surveillance. Norway may have a very fast monitoring and reporting system that efficiently tracks everyone who has been vaccinated and reports any adverse consequences quickly.
We expect surveillance reporting from other countries with active vaccination programs shortly, bringing more data essential for building a more accurate picture of vaccine safety across populations.
The Norwegian reports will sensitize other countries to keep a close eye on vaccine recipients, especially those in nursing homes who are older and vulnerable. We may see more reports about this from other countries in the coming weeks.
But maybe not. We have limited information on these cases in Norway. The people reported to have died were elderly and very vulnerable. Many had significant underlying health conditions that often occur in very old age and may be nearing the end of their lives regardless of the vaccine.
While 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 seen any trends showing that older people die after vaccination. For example, there is no evidence that the annual flu vaccine has been linked to deaths in the elderly – or people of any age.
However, it is important to note that in making a comparison with the flu shot or another vaccine and the Pfizer vaccine for COVID-19, we are comparing apples and pears.
The Pfizer vaccine is based on mRNA technology, which is completely new in a human vaccine. This technology introduces some of the genetic material of the SARS-CoV-2 virus in the form of messenger RNA (mRNA). This instructs your cells to make a part of the virus that stimulates an immune response that inhibits infection and protects against disease.
All vaccines are designed to trigger an immune response – albeit in different ways – to prepare our bodies to fight the virus if and when we encounter it.
Creating an immune response leads to inflammation in the body. Some people will not experience side effects from a vaccine, but the inflammation can manifest in different ways in different people and between different vaccines. This could mean a reaction at the injection site or tiredness or feeling unwell.
The deaths in Norway were reportedly associated with fever, nausea and diarrhea, which, although at the serious end of the spectrum of vaccine side effects, would be acceptable to the vast majority of people.
We are now beginning to understand how different people will respond to the mRNA. This vaccine may have more serious effects in elderly, vulnerable people, where the initial inflammatory response may be overwhelming.
But it is too early to draw any conclusions.
Side effects show that a vaccine elicits an immune response
Vaccines must generate an immune response in order to work, and side effects are a byproduct of our body building an immune response.
While the deaths are sad, they should not be a cause for alarm. This basically tells us that the vaccine stimulates an immune response. For most people, that response will be completely acceptable and lead to the development of an immune memory that protects you from severe COVID-19.
The big challenge for any vaccine is generating enough immune response so that you are protected from the disease in question, but not too much that you experience serious side effects. Where this line exists in the sand will vary from person to person, but the oldest and weakest vaccine recipients are likely to be at greatest risk of serious, potentially life-threatening reactions.
So for those who are more susceptible, we may want to be a little more careful. By approving the Pfizer vaccine, the TGA may consider not recommending this particular vaccine for people who are very elderly and vulnerable, especially those who have other conditions and may be nearing the end of their lives.
Ideally, the vaccine for this group should be considered on a case-by-case basis, 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 has been republished from The Conversation under a Creative Commons license. Read the original article.