“There’s no country that has attained herd immunity to SARS-CoV-2. And, certainly, there are countries with different levels of vaccination. I mean, some countries have over 60 percent of their population fully vaccinated. There are also countries that have had natural exposure to the infection at very high rates. But it hasn’t extinguished the pandemic. We’ve always seen surges even after that. And I think that reflects several factors.
One, I think natural immunity can wane over time. And I think the durability of that immunity does depend on the severity of original infection. When infections are mild and asymptomatic, we can have at least weighting of neutralizing antibodies and how that correlates with waning immunity. We don’t know yet, but we know that re-infection, or the getting infected again with the virus, either the same variant or another variant, are far more common than we originally thought. Although there is protection, even over longer duration of time, it’s not absolute.”
** One of just a handful of people on Earth who seems to understand the existential threat that Sars-CoV-2 poses