The Great Unmasking

Plus further up to date information on BA.2

The first bit is simply opinion regarding the CDC and their handling of communications during the pandemic. If you could care less what I think about that, I quite understand. If that’s the case skip to the third paragraph for some important updates regarding the rapidly developing scientific information regarding BA.2 and white tail deer.

As we all know the CDC just relaxed it mask use recommendation to be more in keeping with their new metrics of focusing not on the number of Covid infections, but rather on the capability of the healthcare system to function properly. I may be overly sensitive to communication gaffs from the CDC, but I think a great deal of their problem with public trust, in many cases, has been the result of careless messaging. I’m not going to rehash old territory, but the latest example was their explanation of why they were extending the recommendation to unmask to schools in areas that meet their current metrics for low and moderate disease transmission. The answer was, “… children have a very low rate of severe disease, and the multilayered protections in place in schools prevent significant disease transfer.” Unfortunately that response leads directly to an argument that masks were never needed in schools, and the children were subjected to an unnecessary cruelty for two years. After all, we knew from very early on, that children were spared the brunt of this disease. It actually took a while to even know that they could occasionally become severely ill. The “multilayered protections present in schools,” surface and hand sanitizing, distancing, increased ventilation and HEPA air purification have all been in place for quite a while - so nothing new to see there.

Instead of providing fuel for a fallacious argument that masks were never needed, I wish the CDC had simply stated that they were applying the same new metrics to children in schools that they were using for the communities at large. They could have stressed that at earlier periods in the pandemic, when disease transmission was higher and the healthcare system was on the brink of collapse, we depended on the proven ability of masks to reduce school clusters of contagion. Children infected in school carry the disease out into the community and the home, and the secondary cases in adults, as well as children, would have added to the burden on the hospitals. Having large clustered outbreaks, with the attendant need for quarantine and isolation, was a major factor in forcing school closures. Masks were an important tool that reduced large outbreaks and strengthened our ability to provide in person learning. Now that a combination of vaccine and natural immunity, improved therapeutics and a somewhat milder infection called Omicron, which is rapidly receding, the new situation has allowed us to determine that it is safe for the children to unmask if they and their parents wish to.

Now for a brief further update on some important epidemiologic data on BA.2. Last week’s post contained a review of the laboratory data suggesting that BA.2 was a bit nastier in cellular models and in hamsters, then the original Omicron variant. Hospitalizations in Denmark and South Africa however have not suggested that the more rapidly spreading BA.2 variant is more severe. The question remains whether recovery from Omicron will be providing sufficient cross immunity to prevent rapid infection with BA.2. This is a valid concern since the two variants, even though related, differ by 40 mutations. A preprint out this week from the Danish Statens Serum Institut provides us with some early information. Out of 1.8 million cases of infection from the last week of November through mid February they found 1,739 with reinfection during a short interval following the initial infection (20-60 days). Without going into too much detail, the results of their analysis show that reinfection with BA.2 after Omicron does occur, but is relatively uncommon. Almost all the cases noted occurred in young unvaccinated people (89%), and the infections were all mild. Rare cases of reinfection with Omicron itself were also observed, again in the same demographic. Putting the laboratory and now detailed epidemiological data together, I would say that the information so far strongly suggests the vast majority of people with immunity from prior Omicron infection- and let’s face it that will be a very large swath of humanity- will have very good, at least short term, protection from BA.2 infection. A small percentage of previously unvaccinated people may be susceptible rather quickly following recovery from Omicron, but assuming they have a normal immune system the illness should be mild. BA.2 looks to be continuing the trend of devolving into the endemic level nuisance, and I’m demoting it from scariant to just another tag along killer of the vulnerable unvaccinated and previously uninfected. Right now the most visible scariant that we are tracking is Vladimir Putin.

Finally there is some interesting information on the nexus of human and animal SARS-2-Cov19 infections. You are probably aware that a sizable number of mammals have been found to be infected by the virus. In some species it produces serious illness or death, and in other species it is largely asymptomatic. Mink were particularly susceptible to infection by contact with humans, and once the virus was in the farmed mink population it underwent rapid mutational adaptation. The finding of human mink handlers infected with the mink specific strain was strong evidence that the SARS-2-Cov19 virus had jumped back from the animals to humans and precipitated the destruction of all the farmed mink in Denmark in December of 2020.

We have known for some time that a very significant percentage of the White Tailed deer population in various parts of our country are infected with the virus, which spread to them from humans. Once the virus was in the deer population it also underwent rapid mutational change to adapt to the animals, and it’s genetic sequences became highly divergent from human strains of the virus. A preprint this week from Canadian researchers details a unique lineage of the virus in deer with 76 mutations from the ancestral virus and 23 which have not been previously seen in any infected animals. Searching the data base of sequenced human SAR-2-Cov19 viral genomes they located a match in a man who lives close to the area where the virus was found in deer, and who has contact with deer through hunting. This is almost certainly another example of the virus jumping back from animals to humans after undergoing extensive mutations. There are certainly a lot of White Tail deer in the US and extensive contact with humans. How the deer will shape up compared to Putin as a risk for humanity is anyone’s guess, but right now the smart money is on the Russian dictator.