March 4, 2024

“We know this is an overestimation of current vaccination levels,” said Michael Johansson, a researcher at the CDC. “However, we hope that by the end of this period we will reach a higher level.” ”

All viruses accumulate mutations over time; Most mutations go away, but those that offer an advantage – such as greater contagion or faster replication – can take root and spread. In particular, a more transferable variant is likely to spread quickly among the population.

The new coronavirus has accumulated worrying mutations faster than many researchers expected. Some variants also contain mutations that can easily weaken vaccine protection.

However, the immunity induced by vaccines is extremely strong and should last for years, said Paul Duprex, the Jonas Salk Chair of Vaccine Research at the University of Pittsburgh. “It won’t go from 94 percent effectiveness to 32 percent vaccine effectiveness overnight,” he said.

The variant identified in the UK differs from previous versions of the virus by about 20 mutations, including at least two mutations that may add to its greater risk of contagion. As of Jan. 15, it had been detected in more than 70 cases from 13 states – most recently in Oregon – but the actual numbers are likely to be much higher, said Dr. Butler. “CDC expects these numbers to rise in the coming weeks,” he said.

The CDC has sequenced approximately 71,000 samples of the virus, a tiny fraction of the 23 million people who have been infected in the country to date. But the agency has increased its efforts six-fold in the past two weeks, given B.1.1.7 and other variants, said Dr. Gregory Armstrong, who leads the agency’s molecular surveillance efforts.

State and local health labs have pledged to sequence approximately 6,000 samples per week, a goal they are expected to achieve in about three weeks.