With a virus as contagious as the coronavirus that causes COVID-19, any new variants that are even more transmissible than the original can cloud the path to recovery from a global pandemic. In July, the delta variant, which scientists believe is twice as contagious as earlier ones, became the dominant variant in the US and quickly resulted in a spike of COVID-19 cases and hospitalizations. The vast majority of hospitalizations and deaths have been in people who are unvaccinated. On Nov. 26, the World Health Organization named omicron the newest variant of concern.
As of Sunday, 17 US states and counting have reported cases of omicron, or about a third of the country.
“This news is concerning, but it is not a surprise. We know that this virus is highly infectious and moves quickly throughout the world,” Minnesota Gov. Tim Waltz said in a news release from the state’s health department after a person from the Minneapolis area, who had attended the Anime NYC convention from Nov. 19 to 21, tested positive.
After scientists in South Africa identified omicron following a new spike in cases, researchers around the globe started the race to find out exactly how contagious it is and whether it’ll decrease the effectiveness of the COVID-19 vaccines. Last week, President Joe Biden issued a travel ban on eight countries in southern Africa over omicron variant concerns. Omicron has since been detected in at least 45 countries around the world.
Last week, the Netherlands government announced that it had detected omicron in COVID-19 samples taken prior to South Africa’s alert to the WHO, suggesting that omicron has had a footing in Europe for longer than scientists thought.
Right now, scientists think that omicron is likely to be at least as contagious as delta and that the level of contagiousness will strain health care systems if left unchecked. But they’re also confident vaccines will continue to be protective against severe disease, and the same public health measures we’ve been using to curb COVID-19 the last two years will also be effective against omicron. According to Dec. 5 data from the US Centers for Disease Control and Prevention, 75.5% of Americans ages 5 and older have received at least one COVID-19 shot.
On Friday, CDC Director Dr. Rochelle Walensky told Good Morning America that there were about 90,000 new cases of COVID-19 in the US every day, and that “and about 99.9% of them continue to be delta.” As scientists work to uncover omicron, here’s how the two variants compare right now.
Is omicron worse than delta (or vice versa)?
It’s too early to tell for sure, but early signals of the severity of omicron are “encouraging,” Dr. Anthony Fauci, President Biden’s chief medical adviser, told CNN — that is, there aren’t safety signals right now that show omicron leads to more severe COVID-19. In terms of how contagious the two variants are: “Clearly, in South Africa, omicron has a transmission advantage,” Fauci said, noting that we need to be “careful” about drawing too many conclusions before there’s more data, which might take a couple weeks. (There is the optimistic view that omicron outcompetes delta as the dominant variant but is also less deadly, which would change the pandemic for the better. But again, it’s too soon to make that distinction.)
Omicron has some similar mutations in its spike protein to the delta variant, according to the Republic of South Africa’s Department of Health, as well as the alpha, gamma and beta variants — all classified as variants of concern by the WHO. This means omicron will also be very transmissible, likely enabling the virus to more easily get around someone’s antibodies, lowering the vaccine’s efficacy against symptomatic disease (as in the delta variant’s case, scientists expect the vaccines to remain protective against severe COVID-19). Scientists from South Africa also believe omicron may lead to more cases of reinfection in people who’ve already had COVID-19.
Omicron has more mutations on its spike protein than the delta variant does, but whether that means anything remains to be seen.
“What all those changes in the aggregate are going to do for the things that matter for this virus, we don’t really know yet,” Robert Garry, a virologist at Tulane University, told CNN.
What is a mutation or variant?
The coronavirus enters our cells using its “corona,” or layer of protein spikes, then makes copies of itself in our bodies, where inevitably there are some errors or mutations, as explained by Yale Medicine. Sometimes those mutations in the virus are harmless, but other times — like in the case of the delta and omicron variants — they make it much easier for the virus to spread from person to person and infect more people.
The more people who are unvaccinated or without immunity from COVID-19, the more opportunities there are for the coronavirus to spread and form concerning variants.
“I think what you’re seeing is just the manifestation of what we’ve been talking about,” Fauci told NBC Sunday. “Why it is so important for people to get vaccinated, and for those who are fully vaccinated to get boosted.”
Apart from vaccine hesitancy, many people in countries outside the US don’t have access to a COVID-19 vaccine. According to Our World in Data, 6.2% of people in low-income countries have received a dose of coronavirus vaccine.
“The emergence of the omicron variant should be a wake-up call to the world that vaccine inequality cannot be allowed to continue,” South Africa’s president, Cyril Ramaphosa, said in an address.
What are the symptoms of omicron vs. delta?
So far, people who have come down with COVID-19 from the omicron variant in the US appear to have (or had) mild symptoms.
Dr. Angelique Coetzee, a South African doctor who helped discover omicron, told the BBC that so far, patients she’s seen with the omicron variant have “extremely mild cases” of COVID-19. Those symptoms included fatigue, headache and a scratchy throat, she said, not the telltale loss of smell or a cough associated with earlier COVID-19 infections.
However, the delta variant may have slightly changed the way COVID-19 presents. Cough and loss of smell are also less common symptoms of COVID-19 caused by the delta variant compared with earlier variants, per the Baton Rouge General, a Mayo Clinic network. Cold symptoms like a headache and runny nose are now more common symptoms of COVID-19, according to the UK’s ZOE COVID Study.
In general, it’s too early to make a claim that omicron has milder or more severe symptoms than delta. Although anecdotal evidence shows that confirmed cases caused by omicron have shown mild symptoms, most of those people have been younger adults, according to South Africa’s health department. Younger adults and children are generally less likely to experience severe COVID-19 than older adults.
How do you test for omicron?
A COVID-19 test won’t tell you which variant you have. In order for scientists to determine whether it’s omicron or another coronavirus variant, the US Center for Disease Control and Prevention uses genomic sequencing. According to CDC Director Dr. Rochelle Walensky, the US is now testing 80,000 positive COVID-19 samples per week (about one in seven positive tests), up from 8,000 per week earlier this year.
Fortunately, the omicron variant is easily detected through PCR tests, according to Fauci, which can then be confirmed through labs that use genomic sequencing.