COVID-19 briefing: Omicron variant is likely everywhere while delta cases are on the rise

Delta remains dominant around the world while omicron emerges, though time will tell whether the new variant will challenge vaccine effectiveness

The omicron variant of SARS-CoV-2 has most likely spread around the world already, but ineffective COVID-19 testing will continue to hamper scientists' ability to say anything definitive about the latest strain for several more weeks, according to two Johns Hopkins University experts.

Bill Moss and Jennifer Nuzzo

Image caption: Bill Moss and Jennifer Nuzzo

Meanwhile, infections continue to rise in the United States and internationally—especially in Africa and Eastern Europe where vaccination rates continue to lag behind the rest of the world, the experts said Friday during the Coronavirus Resource Center's live briefing.

"At this point we should assume the omicron variant is near everywhere," said Jennifer Nuzzo, the center's epidemiology lead. "But how much of it we really don't know. And where it started we really don't know. And who it's affecting we really don't know—because our surveillance is very limited and also potentially biased."

Testing for omicron cases has been primarily focused on travelers who are typically young and healthy, said Nuzzo, senior scholar at the Center for Health Security at the Johns Hopkins Bloomberg School of Public Health.

"The body of evidence that we have so far, which is very limited, suggests the potential that it may be more transmissible than the delta variant," she added. "We don't yet have any evidence of increased severity."

The scientific community's understanding of omicron will change as it makes its way into older and more susceptible populations, Nuzzo said.

"As we are trying to learn about this variant in real time, our data is very much imperfect," she said. "But the virus that remains dominant is still the delta variant."

And cases in the United States continue to increase, she added—"not a great place to be starting from when we're talking about a new variant."

U.S. cases have increased 6.1% over the past two weeks, according to an analysis by Emily Pond, a research data analyst for the Center for Health Security. The increase is far higher compared to last Friday, but the jump is partially the result of many states not reporting on the day after Thanksgiving.

The past week's average daily case count was about 101,000, down 45% from a year earlier when it was 184,000. The northeastern United States, which reports high vaccination rates, is experiencing the largest surge—especially in New Hampshire, Rhode Island, and Vermont.

Approximately 9,700 COVID-19 deaths were reported in the United States over the past week, a 12.4% increase from two weeks ago. Last year at this time, the past-week death toll was 13,626.

The 58,885 inpatient hospitalizations, including 13,910 admissions to intensive care units, reported over the last week are also up from two weeks ago by 16% and 13%, respectively, Pond's analysis shows. But they were twice as high a year ago. And the test positivity rate remains above 5% and has been increasing.

"That is always a sign that we need to do more testing," Nuzzo said. "We need to cast a wider net to find infections."

Despite the uncertainty about the omicron variant due to the lack of testing, the U.S. government recommended that all adults over the age of 18 receive a booster dose of the COVID-19 vaccines.

But William Moss, the vaccinology lead for the Coronavirus Resource Center, said there is not enough evidence to know how effective the booster doses will be against omicron.

"We have to be cautious about what we're achieving with booster doses and what we can expect," said Moss, executive director of the International Vaccine Access Center. "We don't yet know how much protection we're going to get with our current vaccines against omicron."

Moss said he believes the vaccines may demonstrate reduced effectiveness against omicron infection but sustained protection against severe disease.

In addition to expanding who can receive booster shots, several pharmaceutical companies are developing new vaccines to target omicron—developments that Moss said will "further exacerbate the global inequities in vaccine distribution."

More than 4.3 billion people, or nearly 56% of the world's population, have received at least one dose of a COVID-19 vaccine. And 45% of the global population is fully vaccinated. Both are "remarkable achievements," he added.

"But we still have these gross inequities," Moss said.

CRC data shows that 35% of the 43 countries with populations over 1 million and case increases of 10% or more are located in sub-Saharan Africa, which has some of the lowest vaccination rates in the world. Across the entire continent, only about 10% of the population has received a single dose, Moss said.

Nigeria, the continent's largest country by population, has a vaccination rate of 1.7%; Ethiopia's rate is even less— 1.3%.

"If there's widespread transmission in sub-Saharan Africa, we're going to see more variants," he added. "This is a huge global problem. We really need to do all we can to decrease these inequities because we're all going to pay the price."