Welcome to the Great Reinfection

I'm afraid your dalliance with the sars-coV-2 virus might not have been your last, if you were unfortunate enough to have had an intimate encounter with it. Prepare for round two and maybe four. The Great Reinfection is here.

Juliet Pulliam says that re infections were rare in the early months of the Pandemic.

Two years have passed and the novelty has largely dissipated. A perfect storm of waning immunity, loosened restrictions, and an extremely transmissible variant making the rounds has meant re infections are the new normal for many. It makes sense that there are more re infections now than ever. The sheer number of people who have had Covid-19 would make repeat infections more common. You can't get reinfecting if you've already been exposed.

It's not surprising that the virus has changed a lot, says a University of Michigan infectious disease epidemiologist. Omicron is similar to an earlier variant in that it is hard to fight off and it wears a wig and makeup.

If re infections are part and parcel of the future of the Pandemic, how common are they? Tracking all kinds of Sars-CoV-2 infections has become much more difficult due to a nosedive in testing and reporting. In the UK, health authorities require at least 90 days between the first and second infections to count as a reinfection. The European Centre for Disease Prevention and Control uses a 60-day minimum between infections.

Since the beginning of the Pandemic, close to one million possible re infections have been identified in England. Almost 100 were a fourth, and over 10,000 were a third.

Pulliam's work tried to put a number on how many infections are actually reinfections. She and her team found that around 15 percent of infections in South Africa are reinfections.

She and her team have looked at how much Omicron has changed things. Over 100,000 suspected reinfections were looked at by them towards the end of the Beta wave in South Africa. They found that the initial protection offered against reinfection was the same all the way through the Delta wave that peaked in July. And then Omicron hit. At a higher number, the risk of reinfection was stable.