Tag: Reinfection

Scientists tried to reinfect people with Covid but found it impossible, even when they ramped up the dose 10,000-fold, according to the latest results from the Covid challenge trials.

An Imperial study appeared this week that was reported in the press as showing that Omicron infection does "virtually nothing" to protect against re-infection. But the study actually shows the opposite.

Natural immunity from previous infection remains strong against Omicron, a study from Qatar has found, with 56% protection against reinfection and 100% protection against serious disease and death.

The CDC in America has published a new study claiming to show that, among the previously infected, the unvaccinated are at more than double the risk of re-infection than the vaccinated. But it has many problems.

Reports that the Delta variant is much more likely to reinfect than the Alpha variant are based on a study that does not look at T cell immunity or any real world reinfection rates.

A new study of over 50,000 employees of the healthcare system in Cleveland, Ohio, has found that previous infection gives very robust protection against re-infection and there is no gain to being vaccinated as well.

Alarmist claims about Covid reinfections are being used to encourage young people to get vaccinated even when they've already had the virus. But dig down deeper into the study being used and the truth is quite different.

Researchers at Oxford University have launched a trial that will deliberately expose people who have already had Covid to the coronavirus again to study the level of immune protection needed to prevent reinfection.

Mike Hearn, author of the most read piece on Lockdown Sceptics, takes apart a new paper in the Lancet purporting to show that 20% of people who recover from COVID-19 are vulnerable to reinfection.

by Mike Hearn A recent paper in the Lancet claims that one in five people might not get immunity from being infected with COVID. The study is invalid. Although these sorts of problems have been seen before, this is a good opportunity to quickly recall why COVID science is in such dire straits. The research has a straightforward goal: follow a population of Danish people who tested positive in Denmark's first wave, and re-test them during the second wave to see if they became infected a second time. Denmark has a large free PCR testing programme so there is plenty of data to analyse. Out of 11,068 who tested positive in the first wave, 72 also tested positive during the second wave. This fact is used to advocate for vaccination of people who've already had COVID. The obvious problem with this strategy is that false positives can cause apparent reinfection even when no such thing has happened. The paper doesn't mention this possibility until page 7, where the entire topic is dismissed in a single sentence: "Some misclassifications by PCR tests might have occurred; however, the test used is believed to be highly accurate, with a sensitivity of 97·1% and specificity of 99·98%." My curiosity was piqued by this figure because, as I've written about previously, at least as of ...