COVID At A Crossroads
In this issue we will focus exclusively on COVID-19 as 2023 has seen a fundamental(although not necessarily correct) shift in how we are approaching SARS-CoV-2 andthe clinical consequences of infection.
As always, we will start with fundamentals and along the way answer the commonquestions we are hearing in the clinic.
This significant decline is more readily apparent when we look at prevalence(number of active cases per 100 County residents). In mid to late July 9.7% of the population had an active COVID infection, and now it is 0.4%.
So to answer the epidemic versus endemic question, it looks like we are approaching endemicity with a base expected incidence rate of 8-10 new daily cases per 100,000 population and a prevalence rate of 0.3-0.4%. For large portions of the year we experience this low, steady rate of community transmission but at other times we are having significant surges in activity. The question being – can we predict when those surges might occur? More below..
As of January 26th, 2023 Evusheld is no longer authorized by the FDA and will be unavailable to patients. This is a significant and alarming development for immunocompromised individuals as well as those who did not tolerate vaccinations /boosters and relied on Evusheld’s protection. The FDA estimated that “fever than10% of circulating variants in the US causing infection are susceptible to the product.”
This decision was based not on epidemiologic data but instead on laboratory experiments (nevertheless valid) which showed as early as May of 2022 that theBA.4 and BA.5 Omicron subvariants had “escaped or reduced the activity of monoclonal antibodies developed for clinical use” but that Evusheld and Sotrovimab still showed activity (Tuekprakhon et al. link:https://www.biorxiv.org/content/10.1101/2022.05.21.492554v1.full.pdf). In July, Boschi et al. reported that Evusheld’s neutralization was 233 times less active on Omicron than the Delta variant, suggesting of “limited efficacy” (link:https://academic.oup.com/cid/article/75/1/e534/6529556).
Fortunately, there is accruing evidence that polyclonal antibody preparations – suchas plasma from vaccinated and previously infected individuals (terms: convalescent plasma) – would restore protection amongst immunocompromised patients. For amore detailed discussion, readers can refer to this excellent STAT News article – link:https://www.statnews.com/2023/02/06/covid-convalescent-plasma-antibody-therapy/
Our blog posts this and previous months can be found archived on our website at www.drbretsky.com/blog. Our blog post this month covered booster vaccinations
Both BA.4 and BA.5 (included in the currently available bivalent booster) have now essentially vanished according to CDC data. For Region 9 (which includes Arizona, California, Hawaii and Pacific Territories), BA.4 and BA.5 make up only 0.2% of the currently circulating variants, as compared to 3.9% in January and 90.1% in early August 2022.
KBB.1.5 which was 7.0% of the total variant population in early January 2022 is now the most common at 45.8% with BQ.1.1 and BQ.1 at 31.0% and 13.6% respectively. Initial concerns for an increased transmissibility of this variant were based on observations in China which, until recently, had held to a zero COVID policy and has a largely immunologically naive population. As noted above, cases in our region have decreased in January 2023 during the time period when KBB.1.5 increased infrequency. The general consensus had been that KBB.1.5 does not cause any more severe disease than Omicron or its subvariants.
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