COVID-19 Reinfection – It’s Here. Round 2.

Omicron is here and so is reinfection; along with breakthrough infections. The pool of COVID-19-naive candidates is vastly shrinking. In May, 2021, the combined US COVID-19 seroprevalence was 81%. It is now most certainly well in the 95%+ range; however, Omicron does not seem to care about COVID-19-naivety.

  1. Reinfection is expected. In our August, 2021 post, we described immunity and how we all will be exposed to COVID-19 again and again

  2. The Omicron COVID-19 variant is following expected seasonal patterns that we described this past November.

  3. Omicron reinfection is 90% less severe than original infection (there is a 90% lower chance of Omicron resulting in hospitalization or death). 

The Big Questions

  1. If you had a documented prior case of COVID-19, should you get the vaccine/booster? Yes. A study from EPIC showed a 44% greater chance for reinfection (compared to those vaccinated).

  2. If you have been vaccinated (with 2 doses of the mRNA vaccine), what is the reinfection risk vs. no vaccine? A study from QATAR published in CIDRAP showed a 65 – 82% lower breakthrough infection risk for those with 2 doses of an mRNA vaccine vs. the unvaccinated. Sadly, receiving two doses of vaccine will likely not prevent symptomatic disease (it’s only ~20% effective), but getting a booster will provide 55-80% prevention.

  3. Will Omicron bring on more reinfection than the Delta strain? Yes. Omicron has a 5.4-fold higher risk of reinfection than Delta (according to a UK National Health Service Study).

  4. Will prior infection protect a person from getting reinfected with the Omicron variant? No. Only 19% of people with a prior infection were protected from Omicron in the UK study.

  5. Will prior infection protect a person from getting infected from the Delta strain? Sort of. Prior infection offered 85% protection from the Delta strain in the UK study, but that point is likely moot as Omicron is taking over.

Cyclic Nature of Coronaviruses

The Fitzpatrick Translational Science team knew and have published posts showing the cyclical nature of common cold coronaviruses. Experts predicted that we all will be exposed (either asymptomatically or symptomatically) with COVID-19 again and again, just as we are with each of the other 4 common cold coronaviruses. 

  • The September 28, 2020 COVID-19 Immunity Blog showed the biannual prevalence for the other 4 common cold coronaviruses.

  • The December 8, 2020 COVID-19 EndGame Timeline post calculated the combined vaccination/prior infection immunity estimation (when would we achieve herd immunity?). We predicted that by July 1, 2021 about 87% of the US population would have either been vaccinated or had a prior infection. Here is where we were wrong:

  • There does not seem to be any herd immunity for COVID-19, at least not in the traditional sense. We all are going to get either asymptomatic or symptomatic disease. Even the most popular herd immunity model by Dr. Youyang Gu changed its title to “Path to Normality”. We suggest user’s check out this calculator and play with the variables. The low efficacy of vaccines against Omicron drops population immunity by ~2/3 (from what it was with Delta).

  • Immunity is waning somewhat faster than we predicted. COVID-19 is not following a biannual cycle, but it is indeed following the familiar season (winter) peak.

  • Our January 12, 2021 COVID-19 Reinfection Risk post stated that outside of rare case reports, reinfections were very uncommon, but we predicted they will occur over time as immunity wanes.

  • Our January 12, 2021 post, The Missing Seasonal Flu and Common Cold Coronaviruses, showed the near absence of both the common cold coronaviruses (all 4 of them), as well as seasonal influenza at the beginning of last year’s flu season.

  • Although nearly all of us will be reinfected and/or have breakthrough infections, our immune systems will retain some memory, which should reduce severity.

Risk Stratification

We believe the political polarization of COVID-19 policies is largely due to policy makers not educating people about risk stratification. Since the world is now on COVID-19 round two, recommendations for enhancing an individual’s COVID-19 immunity (receiving boosters) should emphasize risk stratification:

  1. Age of patient. >81% of COVID-19 deaths occur in people >65. Get boosted.

  2. Underlying medical conditions (cancer, kidney disease, lung diseases, liver disease, dementia/neurological conditions, diabetes (1 or 2), down syndrome, heart conditions (CD, hypertension, heart failure, cardiomyopathies), HIV, immunocompromised, mental health, overweight/obesity, pregnancy, transplant patient, stroke/vascular disease, tuberculosis). Get boosted.

  3. Smoker/former smoker. Get boosted.

Omicron Peak

Experts are predicting that the Omicron COVID-19 variant will peak in mid-January. However, because of past incorrect results, some modelers have stopped trying to project out beyond a week. If Omicron and other COVID-19 variants follow similar seasonal patterns, cases should significantly drop in April.

Kevin Fitzpatrick

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