Covid boosters are here to stay according to White House officials. They will likely be similar to annual flu shots, with a new booster to defend against a new variant every year. There were discussions a year ago that suggested drug makers were looking for a common denominator that would be present in all Covid variants, but I doubt that will happen. First of all it’s not easy or it would have been done already for flu shots and Covid boosters. Second, why would drug makers make a universal vaccine when they can sell boosters for new variants every year?
How well will these boosters work? Well, that depends on your first brush with Covid. Was your first contact with Covid when you got sick two years ago? Or was it when you got a vaccine one year ago? My first brush with Covid was when I got two vaccines in the Spring of 2021, whereas my wife’s first contact was when she and I both caught the first Omicron variant of Covid in January 2022. The reasons why your first contact with Covid is important is because of what scientists call original antigenic sin. According to The Washington Post:
More than 60 years ago, a virologist named Thomas Francis Jr., observed that influenza infections in childhood had lifelong repercussions. For decades after, people’s immune systems carry an imprint from their first flu, activating defenses primarily against the original version of the virus they encountered. He called it “the doctrine of original antigenic sin.”
The same thing is happening with the coronavirus. A growing number of studies show that when the omicron variant infects, it causes the immune system to rapidly activate immune memory cells that are already on standby, created by previous vaccinations or infections.
As more and more of the U.S. population is vaccinated or infected, they will be shielded from the worst dangers of the initial Covid variant, the Wuhan-Hu-1 strain, that killed about 1% or more of those who caught it. That suggests my wife will likely have a small measure of a lifelong defense against the Omicron variant, probably still getting it but not as sick as her first time. I will have a stronger defense against the Wuhan-Hu-1 early strain even though I too have caught Omicron.
“Maybe 10 to 15 years from now, we live in a world where the vaccine is birth-year specific or make strain selection decisions that take into account different immune histories in the population,” said Katelyn Gostic, a researcher at the University of Chicago. “I think we need and are actively developing better technologies and better techniques to try to work at the science fiction frontier here, of figuring out these imprinting questions.”
Not all virologists agree how the original antigenic sin plays out in Covid. An article in the Journal Cell claims vaccines have more breadth, the ability to recognize more variants than an actual Covid infection. These researchers make the bold claim in the title of their article,” SARS-CoV-2 vaccination washes away original antigenic sin.”
In their studies [1.], Röltgen and colleagues confirmed previous findings [2.,3.] showing the absence of germinal centers in COVID-19 and the robust formation of germinal centers after vaccination (Figure 1). They extended these studies by examining the fate of both the vaccine Spike mRNA and the Spike protein in the lymph nodes of vaccinated individuals over a 2-month period [1.]. They showed the presence of Spike protein in the germinal centers of lymph nodes for almost 2 months after immunization.
The concept of ‘original antigen sin’ argues that your first exposure imprints to your immune system such that it is your initial immune response even if you are later exposed to variants. However, it is possible that ‘original antigen sin’ does not apply to all vaccinations or possibly that is only applies to certain infections.