Reports of about 30 deaths among nursing home residents who received the Pfizer vaccine have made international headlines.
Given that the Australian Therapeutic Assets Administration (TGA) expects to approve the vaccine imminently and the launch will start next month, this development may seem a cause for concern about vaccine safety.
But there are a few reasons why it shouldn’t be.
What do we know
We have not seen this problem reported in other countries launching the Pfizer vaccine.
Norway reported that about 45,000 people across the country have been vaccinated against COVID-19 so far. Their vaccination program focused mainly on nursing home residents.
In other countries, there may be a greater focus on front-line health workers. So, if there is any association between deaths in the elderly and this vaccine, it may not be obvious yet.
It also depends on the surveillance. Norway could have a particularly fast surveillance and reporting system, which can effectively track all those who have been vaccinated and quickly report any adverse outcomes.
We would soon expect surveillance in other countries to be reported with an active vaccination program, enhancing the key data to build a more accurate picture of vaccine safety in different populations.
Norway’s reports will raise awareness among other countries about the close monitoring of vaccine recipients, especially those in older and vulnerable nursing homes. We may see further reports on this in the coming weeks in other countries.
But you also may not. We have limited information on these cases in Norway. The people they died about were old and very fragile. Many had significant underlying health conditions common in ancient times and could have approached the end of their lives, independent of the vaccine.
Although under investigation, it is important to note that deaths were not definitively related to vaccine complications. Meanwhile, Australian experts have called for calm.
Vaccines and the elderly
In the recent history of vaccines, we have not seen any trend to show deaths in the elderly after vaccination. For example, there is no evidence that the annual flu vaccine has been associated with deaths in the elderly – or in people of any age.
However, it is important to note that when comparing to the flu vaccine or another vaccine and the Pfizer vaccine for COVID-19, 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 some of the genetic material of the SARS-CoV-2 virus in the form of messenger RNA (mRNA). This instructs your cells to be part of the virus that 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.
Creating an immune response leads to inflammation in the body. Some people will not have side effects of a vaccine, but inflammation can manifest itself in different ways in different people and between different vaccines. This may mean a reaction at the injection site or fatigue or feeling sick.
Deaths in Norway have been associated with fever, nausea and diarrhea, which, although at the severe end of the vaccine’s side effects spectrum, would be tolerable for the vast majority of people.
How do we begin to understand how different people will respond to mRNA. This vaccine may have more serious effects in the elderly, vulnerable, where the initial inflammatory response could be overwhelming.
But it is still too early to draw conclusions.
Side effects show that a vaccine generates an immune response
Vaccines must generate an immune response to function, and side effects are a byproduct of our body that generates an immune response.
While deaths are sad, they should not be a cause for alarm. This actually tells us that the vaccine stimulates an immune response. For most people, the response will be fully tolerable and will lead to the development of immune memory that protects you from severe COVID-19.
The big challenge for any vaccine is to generate a sufficient immune response so that you are protected from the disease in question, but not too much so that you have serious side effects. If this line exists in the sand, it will vary depending on different people, but the oldest and most vulnerable vaccine recipients are likely to be most at risk for severe, potentially life-threatening reactions.
So for those who might be more sensitive, we might want to be a little more careful. In approving the Pfizer vaccine, the TGA may consider recommending this particular vaccine to very elderly and frail people, especially those who have other conditions and are nearing the end of their lives.
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 Conversation under a Creative Commons license. Read the original article.