The role of the microbiome in generating a SARS-CoV-2 spike-specific IgA response

COVID-19 vaccines are a miracle of scientific research and innovation that saved countless numbers of lives. At first, it seemed that these vaccines would eliminate the virus from society. However it soon became clear that despite the clear benefits of these vaccines in preventing hospitalization and death, they do not provide complete protection against infection. Indeed, most Canadians have experienced so-called "breakthrough" infections that were not prevented by vaccination. Why did these vaccines fail to protect us from getting COVID-19? Simply put, they were never designed with this in mind given their administration in the arm muscle whereas the virus infects us via the mouth and nose. The muscle route of administration was a good choice at the time because we do not yet know how to induce durable immunity in the nose and mouth through vaccination. Some vaccinated Canadians don't seem to get COVID-19 despite being exposed to the virus in their households, places of study and work. Understanding why this is the case is a very important question because we may gain a better understanding for how to design the next generation of vaccines that have the potential to protect us not only from illness and death, but from getting the virus in the first place. Our team is studying the possibility that our microbiome, the collection of microbes that live in our bodies, particularly in our airways and gut, has an impact on vaccine-induced immunity to SARS-CoV-2. We will study which microbes in the saliva are correlated with stronger immune responses to the vaccine and test these microbes in animal models. Collectively this work will provide new insights into how we can make better vaccines against SARS-CoV-2.