3 February 2022 Blog Post: Declining Cases, Increasing Mortality
Omicron is most certainly on the decline here in Los Angeles as evidenced both by daily and weekly case rates. As with most epidemics that have rapid growth, we also expect to see very steep declines. Omicron is no exception. The increased infectivity of Omicron in comparison to Delta (Summer/Fall 2021) as well as Mu and Lambda (Winter 2020/2021) is seen graphically by the sharp peak dwarfing previous surges,, which has now passed. Omicron peaked at a rate of 449 new daily cases per 100,000 population the week of 1/11/2022. The previous pandemic high prior to Omicron had been 146 new daily cases per 100,00 the week ending 12/22/2020.
The general consensus (and my own clinical experience) has been that Omicron is indeed less severe clinically than Delta and previous variants. While some of this effect is due to vaccination as well as prior infection, data do support that after controlling for risk factors for hospitalization, Omicron infections intrinsically are associated with a reduced risk (Odds Ratio of 0.3) of severe disease (link: https://www.sciencedirect.com/science/article/pii/S0140673622000174)
However, mortality rates due to Omicron in Los Angeles County now are at 0.52 daily deaths per 100,000 – the highest rate since March of 2021. The maximum mortality rates seen during the Delta surge was 0.30 daily deaths per 100,000. Given that mortality rates are a lagging indicator in an outbreak, we might expect these rates to push even higher. The highest mortality rate we have seen from COVID-19 in Los Angeles County was 2.80 daily deaths per 100,000 the week of 1/12/2021.
Even though Omicron is associated with less severe disease, because it was so prevalent in the population it still exerts a demonstrable and significant effect on mortality rates.
𝗦𝗶𝗴𝗻 𝗨𝗽 𝗳𝗼𝗿 𝗢𝘂𝗿 𝗡𝗲𝘄𝘀𝗹𝗲𝘁𝘁𝗲𝗿