CDC is now “monitoring” the XBB-Covid variant, considered the “most vaccine-resistant strain ever”.

US health chiefs are “monitoring” a new Covid variant feared to be the “most vaccine-resistant yet” after sparking a spiral of cases in Singapore.

The Centers for Disease Control and Prevention (CDC) said the strain — dubbed “XBB” — is still “very rare” in the US, with just 52 cases detected in 15 states so far.

But in a variant update today, they confirmed they were “keeping a close eye on it” after Singapore’s cases doubled in two weeks.

Health chiefs are also tracking BQ.1 and BQ.1.1, which they said is spreading “relatively quickly” on American soil.

They now account for one in five infections, double what it was a week ago.

XBB is another Omicron variant spin-off and has been blamed for the sudden spike in infections in Singapore.

The alarm was sounded by experts like Dr. Raj Rajnarayanan of the New York Institute of Technology, who said it was the “most immune dodge to date.”

However, there is no evidence that it is any more likely to cause serious illness or death compared to its parent or sister strains, all of which have been shown to be mild to most.

Figures show an average of nearly three people die from Covid in Singapore every day.

While in the past there were only one or two dominant global variants, the virus now appears to have fragmented into a swarm of closely related subvariants.

Just last month, scientists were concerned about BA.2.75, which launched from South Asia. In the US, there was concern about strain BA.5, which is now dominant.

The graph above shows the infection rate in Singapore per million inhabitants. After spiraling with the emergence of the XBB variant, it is now showing the first signs of a peak

Three deaths from Covid are currently being registered every day. So far there is no evidence that XBB causes more serious illness or increases the risk of death from Covid

The chart above shows the proportion of cases in Singapore by variant. It shows that XBB (red) has risen sharply in the country

The above shows the percentage of variants in the United States for a week. Officials are keeping an eye on BQ.1 (light green), which is now behind every tenth infection

This map shows the different proportions in the United States. BQ.1 is represented by light green while BQ.1.1 is the darker green

XBB arrived in America on September 15, data shows, and has now been spotted in 15 states.

Most cases are in New York, with 22 infections so far, and in California, where it has been detected ten times.

But it has also been recorded in New Jersey, Washington, Hawaii, Michigan, Arizona, Arkansas, Minnesota, Nebraska, New Mexico, North Carolina, Ohio, Texas and Virginia.

Limited testing for Covid – currently at its lowest level since the pandemic began – and variant surveillance mean this is likely to undercount the true extent of infections.

The CDC revealed that it is keeping an eye on XBB today, saying: “The CDC is also keeping an eye on a subline called XBB based on international reports.

‘[But] it is still very rare in the United States.’

On a separate variant, they added: “BQ.1 and BQ.1.1 are offshoots – grandchildren, if you will – of BA.5, which has been dominant for months.

“CDC data shows that they appear to be spreading relatively quickly, but they still account for a small proportion of total variants.”

The World Health Organization (WHO) also announced that it is monitoring the XBB variant this week.

XBB has mutations in its receptor-binding domain, a key part of the spike protein that virus-fighting antibodies attach to and block infection.

Changes here make the virus less detectable to the immune systems of people who are vaccinated or have previously been infected with Covid.

Singapore scientists estimate that it is 30 percent milder than the previously dominant omicron strain BA.5.

“XBB” consists of two variants with the scientific names BJ.1 and BA.2.75 that have merged.

It was first spotted in India in August, authorities said, but hasn’t sparked a wave so far.

Covid variants can merge – in a process scientifically known as recombination – if they infect the same cell in the same person at the same time and then swap genes.

There have already been several recombinant variants – like “Delta-plus” last year – but none have led to a major increase in infections.

Instead, most are quickly dying out because fusion has made them less contagious than their rivals.

But XBB appears to be the most successful yet, behind 54 percent of Singapore infections, up from 22 percent a week ago.

One possible concern is that Singapore’s reinfection rate has increased dramatically since XBB arrived – from five to 17.5 percent of all cases.

It is not yet clear whether this is simply due to the declining vaccination protection.

There are now early signs that this is peaking, albeit much earlier than expected in mid-November in Singapore.

dr Rajnarayanan counts XBB variant cases in the United States using data from GISAID, the leading variant monitoring platform.

He told DailyMail.com today: “XBB is the most immune fallback yet… that’s why we’re worried.

“XBB can accommodate additional convergent mutations and become fitter.”

It comes as America struggles to kickstart its winter vaccination campaign despite warnings of another Covid wave.

The US is in the process of rolling out a bivalent vaccine for everyone over the age of 5, designed to protect against Covid variants BA.5 and BA.5.

It’s unclear if it also protects against XBB, although scientists say it will still help boost people’s immunity.

A month into the program, only 6 percent of eligible individuals have signed up.

Last week, eligibility was expanded from over 12 to over 5, with American health chiefs saying they should also get vaccinations.

But the move contradicts that in other countries, which are quietly raising the age limit for their Covid vaccinations amid concerns about side effects such as heart inflammation and limited evidence children will benefit

Source: | This article originally belongs to Dailymail.co.uk