Exploring COVID-19 vaccine reactions
Dr. Prescott: It seems to me that it might make sense to get the Johnson & Johnson vaccine next summer after you've gotten the Pfizer or Moderna vaccine this spring. It's a different kind of vaccine, so shouldn't it offer an extra level of protection?
— Dennis Shockley
Dr. Prescott Prescribes
The idea of mixing vaccines is an interesting one, and experts are discussing it. However, it simply hasn't been tested, so we really don't know how it might play out. Unless and until the Centers for Disease Control issues guidance based on scientific data, I'd strongly recommend not doing an experiment on yourself.
Take the first vaccine you're offered and follow the prescribed schedule of shots. Adding additional doses of another vaccine is purely speculative at this point: It could bring benefits, it might do nothing, or it could harm you.
Both Pfizer and Moderna are looking at multiple strategies to protect against potential viral variants, including booster shots and adding a third shot. These approaches, which will be vetted and monitored by regulators, offer the safest and most effective path forward, and I'd await their outcomes.
Dr. Prescott: I read somewhere that younger people tend to have more pronounced reactions to the vaccine because they have more robust immune systems. Does that mean people who experience lesser degrees of reaction also gain less immunity?
— Lea Eldridge
Dr. Prescott Prescribes
Again, we're venturing into the land of hypotheses here, because we simply don't have hard data to answer this question.
I'm unaware of any research showing that young people have experienced more adverse reactions to vaccinations. However, a small study about how those who've already had the virus react to vaccines might be instructive.
It found that people who'd been previously infected, on average, mounted a more robust antibody response to the shots. That same group also more often reported side effects like headaches, fever and chills.
However, in clinical trials of the Moderna vaccine, people who'd been infected actually reported fewer side effects than those who hadn't.
Where does this leave us? Well, confused.
In this climate, it's understandable to worry about the effectiveness of vaccination and to try to figure out if our own shots “took.” Still, it's more important to step back and look at the overall effectiveness of the vaccines.
A study came out last week showing that in Israel, the Pfizer vaccine performed as well in the real world as it had in clinical trials, preventing 95% of symptomatic COVID19 cases. This is yet another heartening signal that, regardless of how you might have felt following your shot, vaccines offer widespread protection across our entire population.