Vaccines are not enough to end this pandemic because vaccines don’t work fast enough. The fundamental problem with vaccines is they train our adaptive immune system to respond to the SARS-CoV-2 coronavirus. Our adaptive immune system is simply too slow to prevent the coronavirus from spreading. “In humans, it takes 4–7 days for the adaptive immune system to mount a significant response.”
[T]here is a delay of 4–7 days before the initial adaptive immune response takes effect…
Principles of innate and adaptive immunity https://www.ncbi.nlm.nih.gov/books/NBK27090/
By contrast, the SARS-CoV-2 coronavirus has an incubation period as low as 1.8 days (with an average of 6 days). The incubation period measures the time from initial exposure until symptoms appear. The catch with COVID is that infected people can be contagious before symptoms appear and sometimes without any symptoms at all. According to the CDC, “[a] person with COVID-19 is considered infectious starting 2 days before they develop symptoms, or 2 days before the date of their positive test if they do not have symptoms”.
Do you see the problem in that timeline? There’s a minimum 4 day delay for our adaptive immune system to respond, but people are already contagious and spreading the coronavirus by then! Our adaptive immune system is like a tortoise racing against a very fast SARS-CoV-2 rabbit that reproduces and spreads SARS-CoV-2 bunnies.
Even though our adaptive immune system is slow, this doesn’t mean vaccines are useless. After all, the tortoise wins the race. After about a week, our adaptive immune system starts to build up an army of antibodies to fight the coronavirus; which are great for preventing death.
The problem with relying on vaccines is our adaptive immune response is slow. This is why we see breakthrough infections in fully vaccinated people and why the fully vaccinated can still spread COVID. Even though fully vaccinated immune systems may be trained to create antibodies against SARS-CoV-2, our immune system needs time to build up that army of antibodies to fight the coronavirus. Once that war is over, our immune system doesn’t maintain a standing army of antibodies. (Which makes sense; it’s expensive to maintain standing armies.) Thus, COVID booster shots.
A COVID booster shot is an additional dose of a vaccine given after the protection provided by the original shot(s) has begun to decrease over time. Typically, you would get a booster after the immunity from the initial dose(s) naturally starts to wane. The booster is designed to help people maintain their level of immunity for longer.
Johns Hopkins Medicine: Booster Shots, Third Doses and Additional Doses for COVID-19 Vaccines: What You Need to Know
Booster shots tell our immune system that the war isn’t over and to keep an army of SARS-CoV-2 antibodies around. So maybe instead of a pandemic, masks and vaccines can get COVID down to an endemic where we just live with it and everyone gets booster shots once or twice a year.
Realistically, will we be OK with frequent booster shots? The annual flu shot is already a hard sell for many people. Will everyone get on board with vaccinations and follow up boosters? We need more weapons against SARS-CoV-2.
Beyond masks and vaccines, is there another tool available to us?
I think so. But that’s for another article.
Disclaimer: Opinions are my own and not those of Google.
