We will likely be shy of the 70% vaccination rate required for herd immunity (see blog post “Likelihood of Herd Immunity”). But what if I’m wrong and we make it to 70%? Will herd immunity last?
I learned three interesting facts this week.
-
People who are vaccinated for Covid-19 can still be carriers of the disease. Despite their bodies not reacting because they have immunity to the current strain, they can still spread it to those who are not vaccinated. This is because people are not prevented from contracting the disease when they are vaccinated - they simply have a lower viral load.
-
People who are vaccinated are less likely to wash their hands as frequently as the pandemic encourages - meaning they could easily have viral particles on the exterior of their bodies. The argument that viral particles cannot live outside the body falls apart because viruses live in hosts, which can be bacterial cells on the outside of the body.
-
Thirdly, people are jumping the gun. Regardless of brand, all vaccines currently take at least 12 days for a person to develop even partial immunity, and some, like Moderna, require 2 doses to be effective. This means if someone was vaccinated last week, there is very little difference between them and someone who was has not yet been vaccinated.
So two vaccinated people interacting won’t spread the disease, but ‘it's okay I’m vaccinated’ isn't a reason you should hug someone.
The good news is that current vaccines are showing effectiveness in preventing the spread of four known variants of Covid-19. Still, pharmaceutical CEOs are saying that boosters will be key and become annual or semiannual recommendations. It is too early to tell what is true - and in times of ambiguity - it's best to remain cautious and continue to test, verify your safety and keep social distancing.