Story at a glance
- The CDC reduced the isolation period from 10 days to five days.
- Omicron seems to be more transmissible than delta, but perhaps not as much as previously thought.
- Omicron exposure might help in the ongoing fight against the delta variant.
The omicron variant of the coronavirus is surging in many places in the world, including in the U.S. Some school districts are delaying returning to classrooms after the holiday break to give teachers, administrators and students time to recover or get tested. Health officials and experts are relieved that additional data about the omicron variant continue to support the idea that it is less severe than delta, but it is still more transmissible and could continue to evolve and develop into a new variant.
Updated guidelines from the CDC
The Centers for Disease Control and Prevention (CDC) reduced the isolation period after testing positive from 10 days to five days for most people, although the individual would need to wear a mask in all public settings for the following five days. People who are unvaccinated or more than six months out from vaccination are recommended to follow those same guidelines. For people who were recently vaccinated or have received their booster, they do not need to quarantine if they are not showing symptoms, but they should wear a mask for the next 10 days.
Omicron may be about 36 percent more transmissible than delta
In a new study uploaded as a preprint and not yet peer reviewed, researchers in South Africa estimate that the omicron variant is 100.3 percent more transmissible than the original version of the SARS-CoV-2 coronavirus and 36.5 percent more transmissible than the delta variant. This contrasts with earlier estimates that omicron was two to five times more transmissible than delta. The team also estimated that omicron has eroded nearly 64 percent of the community’s immunity from previous infections and vaccinations in Gauteng, South Africa.
Omicron exposure may help defend against delta
Research suggests that people who have recovered from the omicron variant of the coronavirus may be better able to fend off the delta variant, which is still circulating at high rates. The CDC estimated that delta made up 41 percent of cases for the week ending with Dec. 25. The laboratory experiment was conducted by scientists in South Africa where omicron was first detected. Experts are hopeful that this surge of omicron could mean that in the future there could be fewer hospitalizations and deaths compared to what was happening with delta.
“Omicron is likely to push Delta out,” said Alex Sigal, a virologist at the Africa Health Research Institute in Durban, South Africa, to The New York Times. “Maybe pushing Delta out is actually a good thing, and we’re looking at something we can live with more easily and that will disrupt us less than the previous variants.”
People with omicron less likely to be hospitalized
New data from the U.K. suggest that people infected with the omicron variant are less likely to be hospitalized than people with the delta variant. The health officials looked at data from 198,348 confirmed omicron cases and compared it to delta cases to better understand the situation in England. The data suggest that vaccines are 72 percent effective against hospitalization from the omicron variant from two weeks after a second dose up to 24 weeks after. This vaccine effectiveness is lower than for the delta variant, but the data suggest that vaccines still protect against symptomatic disease and hospitalization to a certain point.
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