Breaking news: the Omicron wave is burning itself out in South Africa.

A good bit of holiday news is the new finding that the rapid increase in COVID-19 infections in South Africa with the Omicron variant has begun to decline. As quickly as the infections rose, they appear to be decreasing just as fast.

Comparison of COVID-19 infection waves in South Africa. From @rid1tweets.

While this does not rule out a second peak, several things are clear. There is much more background immunity in the population due to the prior waves of COVID infection and vaccination. This likely reduces the number of people who are susceptible to Omicron infection. Therefore, while this highly infectious variant burned through the susceptible population very quickly, since there weren’t nearly as many individuals that could be infected, the wave ended sooner.

Another result of prior immunity (and maybe the virus itself) is an increase in asymptomatic or mild infections. These people would not have been identified since they would not have been tested, so that the peak was actually earlier and number of infectious individuals was greater than thought, leading to a decline sooner than expected.

Reinforcing the mild nature of Omicron infection is the fact that despite large numbers of individuals being infected, hospitalizations, serious illness, and deaths were proportionally less common with this wave.

Illness associated with COVID-19 waves in South Africa. Wave 4 is omicron, wave 3 is delta. Omicron has 3 times the number of cases as delta but only slightly more hospital admissions and fewer severe disease occurrences and deaths.

What does this mean for the United States? 

Potentially the Omicron wave will burn rapidly through the population but cause less disruption, serious illness, and death. But there are several caveats to this hopeful thought.

First, The U.S. population is larger and uses more per capita healthcare resources than South Africa. As the U.S. gets more aggressive with testing, we may also identify more infections that are mild, but use healthcare resources. Thus, the impact on the U.S. health care system may still be substantial.

Importantly, even though we have been through several waves of COVID-19 infection, there are large numbers of unvaccinated and unexposed individuals. Therefore, the number of individuals susceptible to infection with Omicron may be greater in the U.S. than in South Africa.

Therefore, while this news is truly a hopeful sign for the U.S., during this holiday season we need to stay vigilant!

Published by jbakerjrblog

Immunologist, former Army MD, former head of allergy and clinical immunology at University of Michigan, vaccine developer and opinionated guy.

7 thoughts on “Breaking news: the Omicron wave is burning itself out in South Africa.

  1. Best news we’ve heard recently on the pandemic. After a lengthy surge from Delta overwhelming hospitals with very sick people, if would be nice if Omicron was milder and helped further the herd immunity.

    Liked by 1 person

  2. Should we get a 4th shot? Israel is recommending this due to Omicron. I would love your advice on this. Its been over 3 months since my boost (Pfizer).

    Like

    1. Way too early to decide, especially simply based on test tube neutralization tests. One concern, too many vaccinations in too short a time can actually suppress immunity. So this decision needs to be carefully evaluated.

      Like

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