As we head into summer, the wave of cases, largely undetected, in the Northeast and Midwest appears to be receding slowly, but perhaps growing in the South and Southwest. Until we stop all the testing, we will keep seeing this pattern of periodic waves. But some people just don’t want to let go, so it is unlikely we will stop testing and we will periodically see places try to re-implement lockdowns, school closures and mask mandates.
One more piece of evidence on the benefits of a prior infection. In this study during the Omicron wave, among unvaxed persons those who had antibody evidence of prior infection were two-thirds less likely to be infected during the Omicron period than those who did not have antibodies. Level of antibodies did not seem to change the relative risk. (Medrxiv Paper)
This study from Denmark looks at the effectiveness of vaccines in persons with prior infections during multiple waves of different CV variants. Having a prior infection and being vaxed compared to only having a prior infection was associated with 85% vax effectiveness during Alpha, 88% during Delta and 60% during Omicron. In all waves, lessening protection was observed over time. (Medrxiv Paper)
Another study from Brazil also finds that while vaccination of health care workers saw diminshed protection against infection relatively quickly, 60% of subsequent infections were asymptomatic and they vax did seem to limit serious disease. (Medrxiv Paper)
An interesting paper on the issue of excess deaths from CV-19 and the attribution of death to CV-19 looks at life expectancy changes and determines that CV-19 attributed deaths are not an independent cause of death, in other words, when you attribute a death to CV-19, other causes of death decline, suggesting that many CV-19 deaths were merely substitutive in people who had other issues and were likely near the end-of-life. (Medrxiv Paper)
While some studies have shown lower suicide rates during the epidemic, some of that may be masked by drug overdoses which were not characterized as suicides but as accidents. This study from Australia looked at ambulance callouts for self-harm attempts, whether successful or not, and found a sharp increase during the epidemic. This suggests high levels of despair, which result in suicide attempts that are often not successful. (Medrxiv Paper)
It isn’t clear that any of the suppression efforts had any real impact on CV-19 spread. This study from Denmark found that most transmission seemed to occur in confined spaces and contact with a known person and there was limited transmission in community spaces. This would seem to suggest that forcing lockdowns which keep people at home makes little sense. (Medrxiv Paper)
I mentioned issues of virus interactions in the last research summary, and here is another paper exploring the topic in detail, summarizing current research and discussing areas for ongoing study. (Arxiv Study)