Yesterday’s coronavirus briefing by the state indicated that the DOH has all kinds of usual information that it could share if it wants to. As usual, a lot of the discussion was on vaccination, and the department’s efforts to discriminate in terms of who has access to the vaccine, and on the recent case bump. We learned that, according to the department, test positivity is increasing in all ages and hospitalization rates are increasing in all age groups. Have to test that assertion. But we also heard that the median age of hospitalization has declined from 65 to 57 over the last few weeks, and the median age of deaths has declined from 83 to 78. That would appear to be evidence that the higher vaccination rates in the elderly is working. Someone asked a question about why there are still a significant number of LTC deaths. The response was that some residents have not chosen to be or weren’t vaccinated for some reason and that the vaccine is less effective in frail elderly people, which I believe is accurate. I think it also is the case that you have to leave enough time for adaptive immunity to fully develop before you start making assessments of vaccine effectiveness. But the bigger problem continues to be the “zero COVID” attitude. WE NEED TO ACCEPT THAT THERE ARE GOING TO BE CASES AND DEATHS, EVEN IF EVERYONE WAS VACCINATED. We are not, and no other country is, going to eliminate this virus.
Here is the kind of absolute garbage study that the authors should be embarrassed to stick their names on. (Medrxiv Paper) This purports to be a modeling study that shows that if Texas and Mississippi had delayed their ending of mask mandates by a couple of months, huge numbers of infections, hospitalizations and deaths could be avoided. This is exactly the kind of pathetic modeling that should result in prison time for researchers engaging in it. They told the model that ending mask mandates would increase transmission by 67%!! Where do you possibly get a parameter like that? Not in any part of the known universe. Even more embarrassing for the authors, it was published today, and we know now that cases are actually declining in Texas.
Untangling what makes people more infectious is an ongoing and unsettled area of research. (Medrxiv Study) The study comes from England, combining testing results with contact tracing, and examined the association of viral loads with infectiousness. As you would expect, likelihood of secondary transmission increased with viral load as measured by cycle number. According to this study, the B117 variant increased transmission by 50%. Transmission was most likely in a household and by older persons, with children the least likely to transmit.
According to this research, the number of respiratory droplets and aerosols expelled by people is highly variable, largely due to differences in airway resistance to mucus breakup and dispersal. Older and more obese persons exhale more droplets and aerosols. 18% of people were said to be responsible for 80% of droplets and aerosols. This may help explain superspreader events. (PNAS Paper)
More evidence that vaccination induces strong antibody responses, with somewhat stronger ones seen in those with prior CV-19 infections. Interestingly, people who had no reaction to the vaccine had lower levels of antibodies than did persons who experienced some symptoms following vaccination. (Medrxiv Paper)
And a very important paper giving early evidence on the effect of vaccination in Florida. Florida did a particularly good job of getting long-term care residents and seniors vaccinated fast. (Medrxiv Paper) Since February 1, 2021, reductions in cases, hospitalizations and deaths was greater in those 65 and over, who have much higher rates of vaccination, than in those younger than that age. This study looked at the right analysis, relative trends in outcomes by age group, factoring in the pre-existing trends.
Why did Taiwan have such a mild epidemic. The answer is likely largely related to prior exposure to a variety of coronaviruses. This study focussed on the effectiveness of various mitigation measures in the country. (JAMA Article) According to the study, a combination of testing, contact tracing, quarantine and population measures to reduce contacts is necessary to limit transmission.
This is another study attempting to identify the actual number of total cases in the US, based on antibody surveys and other work. (Prev. Study) The samples used in the study were collected from May to July of last year and indicated that there were about 5 undiagnosed cases for every diagnosed one.