Re-infection Take 2
I want to quickly write a post on the recent case of re-infection coming out of the US.
Specifically about the re-infection in a 25-yr old <2 months later, with worse symptoms second time around. Genetic discordance between the two infections was greater than explained by short-term in vivo evolution, ie, presumably two separate infections.
1- While it is harder to discern true re-infection as it requires genetic sequencing of both infections; overall, the incidence of re-infection is fairly low. We have only seen a handful of cases globally despite almost 40M infections.
2- That said, it is always a possibility to get re-infected, and to have worse symptoms upon second infection. This is why wearing masks and socially distancing continue to remain to be important even if you had Covid-19 earlier in the year.
3- Most of the time, your immune system works well. In some cases however, for whatever reason, you either don’t develop an immune response or you develop a hyper response. We see this with other viral infections as well. Unfortunately the 89 year old woman from Netherlands who was re-infected was also undergoing chemotherapy for a form of lymphoma, and sadly died.
4- This is not a reason to believe vaccines won’t work. In vaccine development, we always want an immune response that is stronger than a natural infection.
5- And as always, remember that even if you don’t have circulating B cell antibodies, it doesn’t mean you don’t have immunity. Memory B and T cell responses are equally important, and as we saw in the case of the HK individual, they were able to quickly produce antibodies on repeat exposure.
6- Also, it is very possible that you can still transmit the virus on re-infection, especially if symptomatic but likely also if not symptomatic if the virus isn’t instantly neutralized (more data needed on this).
7- But most importantly: end the herd immunity without vaccination discussion. We know that herd immunity is unattainable due to collateral damage. Now we know that herd immunity cannot eliminate due to potential of re-infection.
More on that here: