Corona-zona

  A couple of months ago, I blogged about the possibility of an endless wash-rinse-repeat cycle of COVID-19 infections. It's possible because of the rate at which the virus is mutating, the genetic space it has left to mutate, and the fact that the mutations seem to be in the direction of greater contagiousness and immune evasion. That is a depressing prospect even if there is no particular reason to fear reinfection except  inconvenience. But this week I have seen a couple of articles that paint a darker picture. One article  on a Canadian independent journalism site invoked the possibility of a "forever plague." They cited cases where people have been reinfected within 23 days .  A CNN story summarized findings of a  VA study  (preprint) looking at cases of reinfections in five million participants. It showed that  compared with those with just one Covid-19 infection, those with two or more documented infections had more than twice the risk of dyin...

  Unless you have no friends, you probably know a lot of people who are vaxxed and boosted and nonetheless are getting infected. If the vaccines work, how can this be? A recent article on the CBS News site asks and answers this question. In a nutshell, current variants have evolved to evade the antibodies generated by vaccines (and previous infections). And those tend to wane after a few months anyway.  That means you can get infected even if you're vaxxed and boosted. But the vaccines are still doing their job of priming your immune system to prevent a serious illness if you are infected. Vaxxed people feel protected from the virus so they let their guards down. They return to risky behavior like eating in crowded restaurants, not wearing masks in public, and so on.   Combine this with a more infectious variant and it's a recipe for a lot of mild infections in vaxxed people. I know a lot of people who have gotten infected recently. To a person they describe it as...

  I don't know about you, but I've been seeing a lot of coverage about the Delta variant that is confusing and concerning. Do the vaccines protect against it, or not? There is still assurance that the vaccines protect against it, and your chances of getting infected are small. Your chances of getting seriously ill are smaller, and your chances of dying are smaller still.   The data seem pretty unequivocal.  Axios just published a good summary : 164 million Americans have been fully vaccinated in the U.S. as of July 31, 2021 0.077% of those have seen "breakthrough" cases (that's 77 in every 10,000, or about 1 in 130) 0.004% of those have been hospitalized (4 in every 100,000, or 1 in 25,000) 0.001% of those have died (1 in every 100,000) According to my favorite risk-of-dying chart, you're more likely to perish from "electrocution, radiation, extreme temperatures, and pressure" than you are to be hospitalized with a breakthrough infection.  You'r...

Last week I had a post about so-called "breakthrough" cases, i.e. people who get COVID-19 despite being fully vaccinated. The post noted that Arizona has a rate more than twice the national average. I asked an epidemiologist I know, who until recently worked at the Department of Health and Human Services, why that might be.  Here are the three answers I got.   Reopening and Mixing "One possibility is that reopening has increased mixing among the population and our case numbers are rising again, meaning more exposures than in places with lower case rates." This is true to some extent in Arizona.   As reported in my most recent by the numbers post, a small increase in infection rates started in Arizona about a month ago. Probably not coincidentally, this was shortly after the governor issued a reopening order .   But the rise wasn't that big, increasing only about 2 cases per 100K over the period. Also Arizona is in the lowest tier of states for infect...

  Now that we have large numbers of people vaccinated, epidemiologists are starting to get a good idea of what rate of "breakthrough" cases we can expect. Those are cases where people who have been fully vaccinated become infected anyway. Public health officials stress that vaccines aren't perfect and breakthrough cases are expected. Here in Arizona, ADHS says there have been 271 cases. In the state we have 1,551,172 people fully vaccinated (according to Johns Hopkins ).  That works out to a rate of 0.017% or one chance in 5,882 of being infected despite vaccination.   Nationally, the rate is much lower.  CDC is reporting  about 5600 cases among 70,811,070 vaccinated people. That works out to 0.008% or one chance in 12,500. In both cases, many infections are asymptomatic. Of those that aren't, few require hospitalization, and deaths are rare. Why the Arizona rate is more than twice the national rate is unknown and something ADHS should be looking into....