The heavily mutated omicron variant's impact on the future of the pandemic remains to be seen as it continues to quietly spread across the nation.
It's been nearly a week since the first case of the omicron variant was detected in Massachusetts on Dec. 4. The mild case was in a fully vaccinated woman in her 20s from Middlesex County who had traveled out of state.
Experts expect more cases will be reported, but many important questions about omicron, like whether the variant is more contagious or deadly, remain unanswered.
NBC10 Boston asked three top Boston doctors on Tuesday to explain how widespread the omicron variant is in Massachusetts and whether it will become the dominant strain during the weekly "COVID Q&A" series.
How many cases of omicron are in Mass.?
No new cases of the omicron variant have been identified in Massachusetts yet, but Boston doctors said it's only a matter of time.
"I expect more cases," said Dr. Shira Doron, the hospital epidemiologist at Tufts Medical Center. What is less clear, she said, is whether omicron will overtake delta as the dominant strain.
"There's nowhere to go but up from here," said Dr. Daniel Kuritzkes, chief of infectious disease at Brigham and Women's Hospital. "Of course, there will certainly be more cases."
The delta variant, they noted, continues to spread rapidly across the state.
"We can't lose focus on the fact that delta is now a huge problem for us here in Massachusetts, as well as across the country," Kuritzkes said. "We really need to be using all of the measures that are available to bring the current surge under control."
The delta variant has propelled a spike in COVID cases in Massachusetts, particularly post-Thanksgiving.
Dr. David Hamer, an infectious disease expert at Boston Medical Center and professor of global health and medicine at Boston University, said delta's dominance was reflected in recent data from the university's sequencing labs.
"It's all delta," he said. "A couple of what we were calling delta plus, but that has not established a foothold. It's pretty much all delta still."
The spike in infections arrives as colder temperatures have pushed more people indoors, people gather for the holidays, and as vaccinated and unvaccinated residents return to many of traditional activities they took part in before the pandemic.
The result puts Massachusetts among the top 10 worst spikes in coronavirus cases in the country. Daily confirmed infections in Massachusetts have returned to levels not seen since mid-January, before any of the three vaccines were available to the general public.
The Boston doctors said they're already feeling the impact of the surge during the weekly "COVID Q&A" series. Hospitals have seen a nearly 134% increase in COVID-19 admissions over the past month. About 93% of the state’s medical surgical beds are full and 87% of ICU beds are full and local hospitals are struggling to meet the demand.
The omicron variant adds a new unknown to the equation. The Dstate epartment of Public Health did not immediately respond to requests for updated omicron data.
Will omicron overtake delta as the dominant strain?
Many of the most important questions about omicron, like whether the strain is more contagious or deadly, remain unanswered.
"Everybody wants predictions for the future," Kuritzkes said. "A lot of this information, we just have to give some time in order for the data to emerge, and then we'll know what the answers are."
Hamer pointed to preliminary data from South Africa, where omicron was first detected, that indicates the strain of the virus could be more transmissible with less severe symptoms. The omicron variant is rapidly spreading throughout the country and driving a surge of hospitalizations, which could indicate that omicron is replacing delta as the dominant strain.
"Very few of them are on oxygen in contrast to previous waves, so this is encouraging," Hamer said of hospitalizations. "But is this because they have a population that's largely partially immune from past infection, and a little bit of vaccine coverage? Or is it because this variant is causing less severe disease? We don't really have the answer to that question."
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But local experts said there's not enough concrete evidence at this point to make that determination or predictions on whether that will happen in Massachusetts.
"It's very hard to know whether it will co-circulate, whether they'll be sort of even in their distribution -- you know, delta and omicron -- whether it will replace omicron, whether it will, you know, be here in small numbers and fizzle out like some of the other variants have done," Doron said. "It's hard to know because it arrived in South Africa at a time when South Africa was at a very different place."
Based on what's happening in South Africa, Hamer said he has a "gut feeling," that the omicron variant is more transmissible and could eventually replace delta as the dominant strain.
"It's likely to establish a foothold here if it's really more fit than delta," he said. "It's hard to understand the epidemiology but I think there's definitely a risk for that happening and that making worse even as we go into the holidays."
Do vaccines protect against omicron?
In an earlier episode of "COVID Q&A," the experts said they weren't sure if the omicron variant can evade the existing COVID-19 vaccines or natural antibodies.
Shortly afterward, the Pfizer vaccine was reported to be less effective against the omicron variant. However, the drug company said Wednesday that a booster shot may offer enough added protection against omicron, even though the initial two doses appear significantly less effective.