Absolutely nothing noteworthy in the CV briefing yesterday, almost all about vaccination, which the state claims is going swimmingly. Some of ludicrous discussion about equity considerations in vaccination. All that should matter is getting the people most likely to experience serious disease vaccinated first. Once that happens, people can stop panicking about getting sick. Protecting health care workers as a priority makes some sense as well, and then we really should think about vaccinating high-contact individuals, as they are the ones most likely to become infected and cause spread. I am still very concerned about the public reaction when it figures out that vaccination is not absolute protection against infection and won’t make the virus disappear.
Okay, the research just continues to pile up that CV-19 adaptive immunity is pretty strong. The latest is this Science study. (Science Article) The authors looked at antibody, memory B cell, T cell and memory T cell response over an extended period in 188 cases with a spectrum of disease severity. They found that different components of the adaptive immune response displayed different patterns response over time, but that there was a lasting response from antibodies and memory B cells for at least 6 months, while T cell response showed some decline. The response lasted for up to 8 months in some cases.
Similarly, this paper examined immune response in those with serious illness. (Medrxiv Paper) 58 patients who had been hospitalized were studied and most had serious co-morbidities. This group, in this study, had a number of people with a more limited response both in antibodies and T cells than most studies are finding. I am not sure what the difference could be–analytic tests used, or other factors.
Nic Lewis recently pointed out to me a paper that I had read but missed an important aspect of, regarding CT numbers. (JOI Article) The authors were examining the relationship of swabbed samples, CT numbers and culture of live virus. As have other studies, although there is some finding of viable virus at higher CT numbers, almost all of the samples with viable virus had lower CT cycles. It is somewhat astounding that after a year of epidemic we have no standardization of PCR test standards, no routine, ongoing studies associating CT numbers with the likelihood of viable virus and little exploration of other factors which may improve the clinical relevance of the tests that we are primarily relying on to tell us if someone has been infected and may be infectious.
And this study evaluated the utility of salivary viral load as a predictor of disease severity. (Medrxiv Paper) Higher loads were clearly correlated with reduced immune system functioning and more severe disease, including mortality. So again, in regard to PCR tests, figuring out how they can best be used to provide that information is important.
This is an amazingly prescient document, a study from Johns Hopkins on how to prepare for a high impact respiratory virus epidemic, written in the fall of 2019. (JH Paper) I would direct your attention to the material beginning at page 56 and this quote: “The degree to which NPI measures will be effective at preventing or limiting transmission of high-impact respiratory pathogens is uncertain and will largely depend on the context, timing, and epidemiology of the outbreak.” NPI is non-pharmaceutical interventions, i.e. lockdowns, social distancing, etc. Didn’t stop the world from plunging into these drastic measures with no evidence on intended or unintended consequences. As the report says: “Quarantine measures will be least effective for pathogens that are highly transmissible, have short incubation periods, and spread through true airborne mechanisms, as opposed to droplets.” Sounds exactly like what has happened.
The Centers for Medicare & Medicaid Services released a snapshot on CV-19 experience in the Medicare population. (CMS Article) About 62 million Americans are covered by Medicare. There have been about 1,191,000 cases in this population with much higher rates in urban areas than rural ones. The data only runs through October 9 so it has missed the fall/winter wave. It does show the spring and summer waves pretty clearly. There are generally higher rates among minority beneficiaries and much higher rates among those with end-stage renal disease. There have been about 333,000 hospitalizations, with a higher proportion in the spring wave than the summer one.