March 18 (UPI) -- Emerging variants of the coronavirus may mean COVID-19 will remain a persistent threat for years to come, even as case numbers decline and more people are vaccinated, former U.S. Food and Drug Administration commissioner Dr. Mark McClellan said Thursday.
Although increasing vaccination rates in the United States and elsewhere have coincided with decreases in the number of people infected with the virus, it remains unclear just how effective currently available shots and treatments are and will be against new strains, he said.
While the world likely won't experience the alarming numbers of new cases and deaths seen during the first several months of the pandemic, the virus still could become endemic -- a seasonal ailment like the flu -- according to McClellan, director of the Duke-Margolis Center for Health Policy in Durham, N.C.
"While I'm very hopeful we'll be able to get back to some degree of normalcy this summer, that doesn't mean COVID-19 is going to go away," he said during a conference call with reporters.
"The faster we get people vaccinated, the fewer chances the variants have to develop and take hold," he said.
So far, more than 113 million shots of the three available vaccines -- Pfizer-BioNTech, Moderna and Johnson & Johnson -- have been administered across the United States, and more than 12% of the adult population is now fully vaccinated, according to the Centers for Disease Control and Prevention.
Still, in many parts of the country, fewer than 1% of virus samples collected from those infected are undergoing genetic analysis to identify which strain is involved, McClellan said.
This means officials have no real idea of the scope of the spread of emerging strains, which may not respond as effectively to vaccines, he said.
For example, in the United States, fewer than 5,000 confirmed cases have been reported of the B.1.1.7 strain, also known as the "U.K. variant," which was first identified in Kent, England, last September, according to the CDC.
However, McClellan said it is likely that far more have been infected with this strain, which the CDC predicted in January would become the predominant one in the United States by the end of this month.
McClellan said this is significant, and recent research shows the strain is more contagious and up to 100% more deadly than the original form of the virus first identified in Wuhan, China, in December 2019.
Although data on the effectiveness of the currently available COVID-19 vaccines is limited, Pfizer-BioNTech, the maker of one, said its product offered 97% protection against symptomatic disease in Israel between Jan. 17 and March 6.
The U.K. variant was the most dominant strain in Israel at that time, the company said.
Separate studies of the Johnson & Johnson vaccine with another new variant, the "South Africa" or B.1.351 strain, found that the shot still provided protection.
The CDC has set a goal of identifying at least 5% of virus samples nationally by this summer, but countries such as Britain already are performing this analysis on up to 10% of samples, McClellan said.
Another possible hindrance to effective identification of new virus strains is the reduction of COVID-19 testing across the country, he said.
Although this means fewer people are getting sick, it also means public health officials have fewer samples with which to work. Meanwhile, the U.K. variant is fueling ongoing outbreaks of the virus in many parts of California, Florida and Texas, McClellan said.
In addition, on Wednesday, the CDC declared two new strains first identified in California, B.1.427 and B.1.429, "variants of concern."
The emergence of these variants may mean that in the years to come routine vaccination -- similar to the annual flu shot -- against COVID-19 will become necessary to prevent major outbreaks, McClellan said.
"The variants are a real threat, but I do think they can be managed," he said.
"It's going to take continued vigilance, but it involves [virus surveillance] technology we have that we can apply widely because it is not super-expensive," he said.