Omicron & COVID-19 Boosters
Variant emergence has small impact on the who & when of vaccine boosters
On 11/26/2021 the Biden administration announced travel restrictions on non-US citizens coming from South Africa and 7 other African countries due to the emerging Omicron (B.1.1.529) variant of the virus that causes covid-19. Omicron appears to be more transmissible than the current Delta variant while the relative virulence and ability to cause reinfection in the previously vaccinated and infected is unknown. The unusually large number of Omicron mutations has scientists concerned that modifications to the vaccines may be required. Three days later on 11/29/2021 the CDC modified their vaccine recommendations and suggested that everyone ages 18 and older should get a booster shot either when they are 6 months after their initial Pfizer or Moderna series or 2 months after their initial J&J vaccine.
Given the CDC track record of politicizing mask/vaccine policy AND the possibility that the vaccine may need to be modified to deal with Omicron, should we all simply follow the CDC guidance to get the booster now or does waiting for a better vaccine make sense for some people?
Fortunately this time the guidance from the CDC is based on sound science, with some caveats (see below). The CDC relied heavily on a large, high-quality study from Israel that compared covid reinfection rates between those receiving a booster dose of the vaccine with those that only had 2 doses of the Pfizer-BioNTech vaccine.
The results were unambiguous: those in the study that only had two doses of the vaccine were 8 times more likely to be hospitalized with covid reinfection and 6 times more likely to die. The booster vaccine was deployed to a large percentage of the Israeli population over time by age group starting with the most vulnerable age group: those over 60. As can be seen in the graph below, as each successively younger age cohort becomes eligible for the vaccine booster the incidence of covid in the population for that age group shows significant decline.
The Israeli study matched subjects in the booster and control groups demographically, including the time interval from the second vaccine dose. All subjects had been vaccinated the second time between 5 and 10 months prior to the study. Thus the study clearly demonstrates the waning effectiveness of the Pfizer covid-19 vaccine after as a little as 5 months.
The waning vaccine effectiveness brings us to the CDC guidance caveats I mentioned earlier. The CDC again neglects to mention that those that have been previously infected with covid-19 (potentially 40% of the US population) have much more effective and durable immunity to subsequent reinfection. Multiple research efforts have shown that the immunity from natural infection lasts at least 10 months, likely years. Consequently, those in the low risk categories with laboratory-confirmed previous infections could easily wait until the first half of 2022 to receive a covid vaccine booster, at which time it may have been reformulated to better protect against variants if necessary. It is highly likely that natural immunity will provide greater protection than the RNA vaccines (Pfizer and Moderna) against Omicron because natural immunity primes the immune system to the whole virus and not just the spike proteins which are highly mutated in Omicron.
It is important to note that those with the standard 2 doses of the vaccine are generally safe from severe Delta variant covid (and likely Omicron too). The Israeli study found that for the under 40 years of age group that did NOT receive the booster the incidence of severe covid-19 reinfection was only 2.5 / 100,000 and the rate of severe covid reinfection for individuals that did not have comorbidities of ALL ages without the booster was only 3 per 100,000. Therefore, healthy and under age 40, doubly jabbed individuals are not in great danger at present.
Personally, I’m at low risk of severe covid as a doubly vaxxed, healthy individual, but I will be getting the vaccine booster soon to minimize my chances of getting covid with flu like symptoms (not fun) just as I used to do for the flu, and to protect vulnerable individuals near me over the holidays.
12/5/2021 Update: Initial reports on hospitalizations in the Omicron hotspot of Gauteng Province South Africa show that Omicron has milder effects in hospital patients! Despite soaring Omicron case counts the number of hospitalized patients is low and most patients were admitted for other reasons with covid only being discovered during admission testing.
12/14/2021 Update: An excellent post by Eric Topol on his Substack Ground Truths presents evidence that Omicron has greater resistance to previous infection and old (>5 month) vaccination, thus increasing the benefits from boosters.