It took the new omicron only a few weeks to justify gloomy predictions about how infectious it is, but scientists still don’t know if it causes more serious illness, even as the world is facing explosive cases just before Christmas.
“It’s more risky now because the omicron is much more contagious,” said Dr. S. Wesley Long, who runs a testing laboratory at Houston Methodist Hospital, “and has canceled numerous plans to prevent contamination in the past week.
Federal health officials said Monday that Omicron is the dominant option in the US, accounting for about three-quarters of new infections last week.
The speed with which it outpaces the also highly contagious delta variant amazes health officials. After three weeks, omicron accounts for 80% of new symptomatic cases diagnosed by Houston Methodist research centers. It took the delta variant three months to reach that level, Long said.
The mutant’s ability to spread faster and evade immunity came at the wrong time – just as the amount of travel increased and many people lost their vigilance. But what the omicron wave will mean for the world is still unclear because many questions remain unanswered.
Here’s the latest news on the omicron and what remains to be seen.
HOW MANY PROTECTION DOES VACCINES OFFER?
Vaccines in the US and around the world do not provide the same protection against the omicron as against previous versions of the coronavirus. However, vaccines still help – very much. Laboratory tests show that while two doses may not be enough to prevent infection, boostering a Pfizer or Moderna vaccine produces antiviral antibodies that can fight omicron.
Antibody levels naturally decline over time, and the booster raised them again, 25 times for the extra Pfizer shot and 37 times for Moderna. No one knows for sure which level is high enough or how long it will take before antibody levels begin to fall again.
“After booster vaccination, protection against omicronic infection is still about 20% less than protection against the delta variant,” said Dr. Egon Oser of Northwestern University.
But if the virus overcomes this first line of defense, the vaccinated will receive additional layers of protection.
“Vaccines will protect you from serious illness, hospitalization and death,” said Houston Methodist Long. “And this is really the most important thing.”
These additional defenses include T cells, which are mobilized to resist the virus, and memory cells, which, when reactivated, tend to produce more and stronger antibodies.
What about natural immunity?
Previous infection does not appear to provide sufficient protection against omicronic infection, although, like vaccination, it may reduce the likelihood of serious illness.
In South Africa, where omicron is already widespread, scientists have reported a spike in reinfections that they did not see when two previous mutants, including Delta, moved around the country.
In the UK, a report from Imperial College London on Friday showed that the risk of re-infection with omicron was five times higher than the earlier delta variant.
Health experts say anyone who has survived a COVID-19 attack should still get vaccinated because the combination tends to provide better protection.
WHY ALSO IS OMICRON DISTRIBUTING SO FAST?
Scientists are trying to decipher dozens of mutations carried by the omicron to figure out what else is going on. Researchers in Hong Kong recently reported that omicron can multiply in the airways faster than delta, although not as efficiently in the lungs.
What scientists cannot measure is human behavior: in many places there have been mitigating restrictions, winter forced gatherings in enclosed spaces, and travel has skyrocketed just after the omicron began to spread.
DOES OMIKRON CAUSE A PERIODIC DISEASE?
It is still too early to know, especially when you consider that if the vaccinated develop a breakthrough infection, it must be milder than if the omicron attacked the unvaccinated.
Early reports from South Africa suggested a milder illness, but doctors were unsure if this was because the population was quite young, or if many retained some protection against recent delta infection.
And this UK study found no evidence that the omicron was milder than the delta in the UK, even in young adults who might have expected milder illness, with higher rates of omicron infection.
“There is a hint, and I think many of us are hoping that the omicron will be less serious. But I don’t think we can bet on this farm. We’re still talking about SARS CoV-2, the virus that has killed millions of people, ”said Dr. Jacob Lemieux, who is tracking options through a research collaboration led by Harvard Medical School.
WHO IS MORE AT RISK?
Based on the behavior of the other options, “if you are older, if you have comorbidities, if you are obese, you are more likely to have a serious illness. I don’t think it will be different from other options, ”said Dr. Carlos del Rio of Emory University.
But even if you don’t get very sick, an omicronic infection will surely ruin your vacation. Experts agree that, in addition to vaccinations and boosters, it’s wise to go back to the basics of protection: wear masks indoors, avoid crowds, and keep your distance.
AP Science writer Laura Angar contributed to this report.
The Associated Press Department of Health and Science receives support from the Howard Hughes Medical Institute’s Department of Science Education. AP is solely responsible for all content.