RISE OF COVID VARIANTS WILL DEFINE NEXT PHASE OF PANDEMIC
Surge prompts some states to seek change in vaccine strategy
Variants of the coronavirus are increasingly defining the next phase of the pandemic in the United States, taking hold in ever-greater numbers and eliciting pleas for a change in strategy against the outbreak, according to government officials and experts tracking developments.
The highly transmissible B.1.1.7 variant that originated in the United Kingdom now accounts for 27 percent of all cases in this country. It is the most common variant in the United States, Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention, said Wednesday — a development that officials predicted months ago. Two other variants, which took root in South Africa and Brazil and also are more transmissible, are cropping up with increasing frequency in parts of the United States.
The bottom line on all three remains positive. In laboratory tests, vaccines are just as effective against the variant identified in the United Kingdom as they are against the origi
nal strain of the virus. And there is only a modest dropoff in their effectiveness against two others.
“These variants emerged because we continued to give the virus more chance to spread,” said David Ho, whose lab at Columbia University is leading the research on the P. 1 variant first discovered in Brazil. “The sooner we vaccinate everyone, the faster we will contain the viral spread and reduce the chance for new variants to emerge.”
But the overall picture hides problems in some places. One or more of the variants — which also cause more severe disease than the original version of the virus — are racing through the Northeast and the Midwest. That has prompted officials in some communities to ask for more vaccine than they would receive under the government’s population-based formula. Officials in the Northwest are watching a major outbreak of the P. 1 variant in British Columbia.
Michigan also has asked for more vaccine to control an astonishing surge during which its average daily coronavirus caseload rose from 1,503 on March 7 to 7,020 Wednesday, according to CDC data analyzed by The Washington Post.
Asked whether the administration would change its strategy, Andy Slavitt, senior adviser to the White House coronavirus response team, said that the government already is able to move vaccine supply from other parts of a state to harder-hit areas.
“We are getting the amount of vaccines we think are needed for the population because that’s fundamental,” Slavitt said. “And then we are working on very tactical areas ... how to maximize that vaccine distribution so we get the things we want: efficiency, health equity and the other goals that we have.”
In addition to those three variants, the CDC considers two in California “variants of concern” and is watching them closely. It is also monitoring a variant found in New York City.
With most of the rest of the world far behind on immunizations, the virus will continue to spread and mutate, every copy with the potential to spark a variation that current vaccines will not be able to control. The odds of that remain low, experts think, but they are not zero.
“I fear there will be one terrible variant that will come out and take us back to square one,” Ho said.
But experts said vaccines can be boosted, and new ones developed, to address any variants that emerge.
As of April 6, there were
16,275 cases of B.1.1.7, 386 of B. 1.351, first discovered in South Africa, and 356 of P. 1 in the United States. Experts think the actual numbers are much larger, but because the U.S. effort to sequence the genomes of the virus lags, it is difficult to know how widespread the variants truly are.
“The landscape is this big explosion of U.K., the worrisome uptick in P. 1 and then other strains as well,” said Daniel Jones, vice chair of the Division of Molecular Pathology at Ohio State University Wexner Medical Center. Within a few weeks, he said, there will be enough infections in the United States to gather better data on immune response from people, rather than through
tests in a laboratory.
Lab tests usually involve looking at one mutation at a time; the variants circulating can have many, said Stephen Kissler, an immunology expert at the Harvard T.H. Chan School of Public Health.
And “the human immune system is much more complex than we can emulate in a petri dish, so we can only get partial information,” he said.
Found in more than 24 countries and 25 U.S. states, P. 1 is thought to be up to 2.2 times as contagious and 61 percent more infectious than the original form of the virus. In other words, it produces a bigger viral load, which probably makes people sicker.
Some experts have wondered whether competing variants have slowed its spread. Northern California, for example, is dominated by B.1.427/B.1.429 cases, while Southern California has a higher share of B.1.1.7.
“We are seeing different variants in different parts of the country competing to take over populations,” said Benjamin Pinsky, medical director of the Stanford Clinical Virology Lab.
For now, B.1.1.7 appears to be dominant, currently comprising about 50 percent of all sequenced cases in the United States.
“My feeling is if you went in a boxing ring with all the variants, the U.K. variant is going to win in terms of transmissibility,” said Peter Chin-Hong, an infectiousdisease expert at the University of California at San Francisco.
That is good news in at least one respect, because studies have shown that vaccines should work on the variant first identified in the United Kingdom. Ho and others said the U.K. variant is most susceptible to the immune response produced by vaccines, with a modest drop-off in effectiveness against the variant first identified in Brazil and a slightly larger decline for the South African strain.
Immune response to the P. 1 type “is going to be better than the South African variant but probably not as good as the U.K. variant,” Ho said.
The variants discovered in California appear to be potentially more benign than the others. Several states with B.1.1.7 surges have reported unusual outbreaks among school-age children that spreads to their communities, but that hasn’t been the case for the California variants.
“We’ve dropped hospitalizations really low” in areas where B.1.427/B.1.429 is becoming dominant, ChinHong said. “You’d expect to see more cases among kids and spring breakers, but we haven’t seen that. It suggests it’s not marking its territories by making younger people sicker.”
Another variant, originally detected in India, has been making headlines in California this week as a “double mutant” because it contains characteristics from the variants first discovered in California and Brazil/South Africa.
Described by Indian researchers on March 24, it was first identified in the United States March 25 in a patient in the San Francisco Bay area.
Pinsky said “it’s too soon to tell how this variant will act. We know how these individual mutations change the virus but we haven’t been able to see how they behave in combination.”