One of the first major, real-world studies of the Omicron variant’s capacity to evade existing vaccines suggested the strain reduces the Pfizer-BioNTech shot’s effectiveness against new infection “materially.”
The study, unveiled Tuesday, was conducted by Discovery Health, South Africa’s largest private health insurer. It was based on more than 200,000 positive COVID tests.
The Pfizer-BioNTech shot is just 33% effective in reducing Omicron-related infection, down from 80% pre-Omicron. The study noted the drop in efficacy is “potentially compounded by waning durability.”
On the bright side, the Pfizer vaccine retains its capacity to reduce hospitalization risk. The shot was 70% effective at cutting Omicron-related hospital admissions (figure below, from the presentation).
That’s considerably lower than the Delta wave, but nevertheless encouraging, as was a finding that adult hospitalization risk was 29% lower during the current wave compared to South Africa’s last flare-up.
Although the results were preliminary, the data appeared to tentatively support the contention that Omicron, while more evasive than prior variants, is associated with less severe disease. The study suggested Omicron infections produce less respiratory distress, for example, and are symptomatic for around 72 hours.
Nevertheless, the prospect of significantly higher reinfection rates is somewhat ominous to the extent it could further delay a return to “normal,” especially until more definitive conclusions are available about the variant’s severity and/or until Pfizer and Moderna develop variant-specific vaccines.
Ryan Noach, Discovery Health’s CEO, cautioned that elevated levels of antibodies among the populace due to high exposure in South Africa “could be a confounding factor for these hospital admission and severity indicators during [the] Omicron wave.” In other words, one should be cautious about extrapolation to other nations. He also said that indexing the Omicron wave to the Delta wave shows Omicron is already some two-thirds of the Delta peak with just 20% of the hospitalizations.
There are concerns about pediatric infection, though. Children under 18 are 20% more likely to be hospitalized when infected with Omicron, although the sample size was small. Apparently, higher incidence of hospitalization among children is consistent with recent warnings from South Africa’s National Institute for Communicable Diseases, which said pediatric admissions rose during the country’s third wave.
Notably, Noach said only 5% of Omicron cases wind up in ICU. That was just a fraction of the 22% from the Delta wave. The figure for the original virus was 18%.
The slide (below, from the presentation) summarizes the study’s key findings and recommendations.
It’s important to emphasize that the study was based on a two-dose Pfizer inoculation. Discovery emphasized that “vaccination remains the single most important intervention to mitigate against severe COVID-19.”
The research was conducted in conjunction with the South African Medical Research Council. Glenda Gray, president of SAMRC, noted that an ongoing, real-world study of the J&J vaccine against Omicron has so far shown no deaths from the variant.
“So that’s the good news,” Gray remarked. “It shows again that the vaccine is effective against severe disease and death.”
Commenting in real-time on the presentation, Natasha Loder, Health Policy Editor for The Economist, wrote that SAMRC sounded “a bit more cautious on the virulence of Omicron.” Although there’s a “de-linkage between infections and hospitalizations,” it’s too early to say whether this is due to virus, prior infection or vaccination.
This data is pretty good so far. With a 3rd shot I imagine it improves even more. But what about the effects on the unvaccinated? That’s really the concern in the United States with 40% of the population not fully vaccinated this one has the potential to cause severe impact.
We will need data from other countries to know if Omicron causes less severe disease(hosp/death).
SA data is quite thorough https://www.nicd.ac.za/diseases-a-z-index/disease-index-covid-19/surveillance-reports/ Rate of pre-existing Covid is very high in SA, so almost everyone has a certain degree of acquired immunity protection. The apparently lower severity of Omicron in SA may be due to almost all cases being re-infections.
Even so, it seems that hospitalizations with Covid in SA are rising – not yet at, but getting near, prior surge levels. https://www.nicd.ac.za/diseases-a-z-index/disease-index-covid-19/surveillance-reports/daily-hospital-surveillance-datcov-report/
This may reflect the math I mentioned in an earlier thread – left unchecked, higher transmissibility eventually dominates lower severity to result in more severe disease.
I imagine the next country to provide useful data might be Denmark, where daily new Covid cases are soaring to >100 per 10,000 and Omicron is rapidly pulling even with Delta as percent of new cases. Compared to the US, Denmark has a lower pct of population without prior Covid infection but a higher pct of population vaccinated, so pct with no protection from either acquired or vaccine should be generally similar to US. So, watch hospitalization data develop from Denmark and other “US-like” countries.
On another hopeful note, at least for some countries and for shareholders, Pfizer’s oral antiviral continues to show high efficacy in both high risk and standard risk populations, including against Omicron. Even in the US, I don’t imagine the drug will be broadly available until later in 1Q22.
In Colorado, Governor Jared Polis has effectively declared covid “over”. He is not mandating masks at the state level and has said that at this point, everyone has had ample opportunity to get a vaccine. I liked his analogy- if it is cold outside, the state does not tell its citizens to wear a coat to prevent frostbite.
If you get frostbite, it doesn’t put me at risk of getting frostbite.
Agreed.
However, hardly anyone is wearing a medical grade mask that actually functions as a barrier to virus entering or escaping the material that the commonly worn masks are made with.
Common low quality masks minimize the risk that you will infect someone else but do little to protect you from someone else.
Since the start of this thing, I have been wearing a homemade mask with two external layers and two internal layers of bonded polyester and weather stripping to ensure good seal. When exhaling sharply, all air exits through the mask and not through the sides. The mask is washable.
I think I get a similar protection as a good fitting N95 but my mask looks better.
The fit is important. You don’t want air coming in from the sides.
Apparently Omicron has “borrowed” some of the DNA from a common cold virus. This has increased the transmission rate of Omicron (over Delta) but has reduced its virulence (deadliness).
Pfizer is working on an Omicron specific update to the vaccine. If hospitalizations are low enough, the updated vaccine may not be necessary. Only time will tell.
I would be fine taking a COVID vaccine once per year at the same time I got my yearly flu shot. That would be very convenient if they could get it that way.