The Centers for Disease Control and Prevention (CDC) has sounded the alarm about new variants that have spread rapidly through the United States, as the agency finds the decline in Covid-19 cases has stalled in recent days.
In the last two months, the cases and hospitalisations in the United States have declined as more and more Americans receive the vaccine. But now the country could be experiencing how new variants might impact current case numbers.
“The latest data suggest that these declines in cases may be stalling,” CDC Director Dr Rochelle Walensky said during a White House coronavirus press briefing on Friday, adding there was a “very concerning shift in the recent trajectory.”
The new B.1.1.7 variant, which was first detected in the United Kingdom, was predicted by scientists to be 40 to 50 per cent more transmissible than other Covid-19 variants. Experts estimated this variant could become the main strain in the United States by mid-March.
“We are now seeing the effects of these variants in our most recent data,” Dr Walensky said. “Our estimates now indicate the B.1.1.7 accounts for approximately 10 per cent of cases in the United States.”
She added that the federal agency was “sounding the alarm” to the public about these variants in an effort to avoid Covid-19 mitigation efforts from being relaxed too soon.
“It is important to remember … things are tenuous. Now is not the time to relax restrictions,” she continued. “I want to be clear, cases, hospital admissions, and deaths all remain extremely high.”
Experts were not surprised the virus was mutating, but what has caused concern was the potential development of a variant that would make the Covid-19 vaccine less effective, thus impacting current mass vaccination efforts.
Several home-grown variants in the US could also be highly transmissible, including one spreading through California and another in New York City.
Researchers from Columbia University revealed this week that in 1,142 samples studied, they discovered 49 cases of a new variant called B.1.526. It was believed to have originated in New York City.
These results were flagged to the public because the B.1.526 shared a similar mutation to that of variants seen in South Africa and Brazil, called the E484K mutation. This mutation could potentially help the virus evade vaccine immunity.
The B.1.526 variant was first detected in November, but it has rapidly spread and become more prevalent within the last couple of weeks.
“It is this novel variant that is surging, alarmingly, in our patient population over the past few weeks,” the Columbia team wrote.
This has influenced the CDC to recommend for states and individuals to not “expand and release” current Covid-19 restrictions.
“We may be done with the virus but clearly the virus is not done with us,” Dr Walensky said. “We must continue to be vigilant.”