Omicron is more resistant to COVID vaccines but has milder symptoms, major study finds

The first major study of omicron, published on Tuesday, found that the new variant appears to cause milder symptoms than previous variants in South Africa and that two doses of the Pfizer-BioNTech vaccine do not offer enough protection against the strand.

The study, led by Discovery Health and limited to South Africa, found that 29 percent fewer people are admitted to the hospital with the omicron variant than with the delta variant. Experts believe this is because omicron’s symptoms are milder.

“This could be a confounding factor for these hospital admission and severity indicators during this omicron wave,” said Ryan Noach, chief executive of Discovery Health.

The study also found that two Pfizer vaccines only gave 70 percent protection against hospitalization, compared with 90 percent with delta. Furthermore, two Pfizer-BioNTech vaccines provided only 33 percent protection against an omicron infection, compared to 80 percent protection against the delta variant.

Boosters, however, may offer more protection. Through laboratory tests, Pfizer found that three shots of its COVID vaccine could provide neutralizing antibodies against omicron.

"Three doses against omicron are almost equivalent to the two doses effectiveness we had against the ... original variant," said Pfizer CEO Albert Bourla.

The study also finds that omicron might be more transmissible than past variants. Even if the variant is milder, officials worry that the numbers of omicron-positive patients will be so large that it might overwhelm health care systems. Reinfection is also higher with omicron.

Experts think it is still too early to know what these findings mean and how they will affect the situation in the world.  

“To-date laboratory analysis has provided early insights into potential reduction in the effect of neutralizing antibodies against the omicron variant. However, there remains urgency around establishing real-world data on omicron across all areas of impact. Our research into omicron is based on a rich and significant sample, and also relates directly to the experience of the first country in the world to face a COVID-19 wave driven by omicron,” said Dr, Noach.

Discovery Health’s study took place in South Africa and examined 211,000 positive cases from November 15 to December 7.