If we're patient, the FDA-authorized vaccines are all excellent at preventing disease (though Johnson and Johnson may have some safety concerns. That's still TBD. Stay tuned).
"The efficacy of these vaccines is outstanding, but that's not realized until two weeks after the vaccination," said Dr. Thomas Russo, the chief of infectious disease at the University of Buffalo's Jacobs School of Medicine and Biomedical Sciences.
Why two weeks? "When you get vaccinated, your immune system gets a to-do list," explained Mark Cameron, an immunologist at Case Western Reserve University who previously helped contain the outbreak of another deadly coronavirus, SARS, in 2003. What does the immune system need to do with the vaccine?
(All three FDA-authorized vaccines don't contain the actual virus, but genetic code showing our cells how to create just a small, specific part of the virus. Specifically, our cells make the virus' spike protein, which is designed to bind to, and ultimately infect, our cells.)
- Our immune system will gradually recognize the spike protein (produced by the vaccine) as an intruder.
- In response to recognizing this foreign spike protein, the bodies' immune cells will cooperate to start producing protective proteins, called antibodies, to protect you against the virus. If you're infected, these antibodies bind to the spike proteins of the virus, making it difficult or impossible for the virus to bind and gain access to our cells. (When inside, the virus hijacks our cellular machinery to mass multiply. It's an effective parasite).
- "It's around the two-week mark that the immune system is producing antibodies at levels that block infections," said Cameron.
Nicole Doria-Rose, Mehul S. Suthar, Mat Makowski, et al. Antibody Persistence through 6 Months after the Second Dose of mRNA-1273 Vaccine for Covid-19 [open], New England Journal of Medicine (DOI: 10.1056/NEJMc2103916)