Variant reported from Europe as well
The World Health Organization has said it is monitoring a new coronavirus variant known as “Mu”, which was first identified in Colombia in January.
Mu, known scientifically as B.1.621, has been classified as a “variant of interest”, the global health body said Tuesday in its weekly pandemic bulletin.
The WHO said the variant has mutations that indicate a risk of resistance to vaccines and stressed that further studies were needed to better understand it.
“The Mu variant has a constellation of mutations that indicate potential properties of immune escape,” the bulletin said.
There is widespread concern over the emergence of new virus mutations as infection rates are ticking up globally again, with the highly transmissible Delta variant taking hold — especially among the unvaccinated — and in regions where anti-virus measures have been relaxed.
All viruses, including SARS-CoV-2 that causes Covid-19, mutate over time and most mutations have little or no effect on the properties of the virus.
But certain mutations can impact the properties of a virus and influence how easily it spreads, the severity of the disease it causes, and its resistance to vaccines, drugs and other countermeasures.
The WHO currently identifies four Covid-19 variants of concern, including Alpha, which is present in 193 countries, and Delta, present in 170 countries.
Five variants, including Mu, are to be monitored.
After being detected in Colombia, Mu has since been reported in other South American countries and in Europe.
The WHO said its global prevalence has declined to below 0.1 percent among sequenced cases. In Colombia, however, it is at 39 percent.
Covid-19 increases the risk of developing myocarditis (heart inflammation) by a factor of 16, providing a strong argument in favor of vaccination, a new US study showed Tuesday.
Myocarditis and an associated risk, pericarditis (inflammation around the heart) have previously been linked to the Pfizer and Moderna Covid-19 vaccines themselves, particularly among adolescent boys and young men.
But the risk is far higher after infection with Covid-19, according to the new paper by the Centers for Disease Control and Prevention (CDC).
The study analyzed hospital records from 1.5 million patients with Covid and 35 million without, to see what percentage had myocarditis, and stratified them by age and sex.
“Overall, myocarditis was uncommon among persons with and without Covid-19; however, Covid-19 was significantly associated with an increased risk for myocarditis, with risk varying by age group,” the authors wrote.
The increased risk among Covid-19 patients was most pronounced in under-16s, who saw a 37-fold increased risk of myocarditis compared to people of that age group who did not have the coronavirus.
This was followed by over-75s, 65 to 74-year-olds, and 50 to 64-year-olds.
The precise underlying cause isn’t understood but it might be related to viral infection of the heart, the study said — or, in under 16s, it could be related to multisystem inflammatory syndrome.
The CDC study pointed to a paper by Israeli researchers published last week in the New England Journal of Medicine that found that messenger RNA vaccines increased the risk of myocarditis three-fold.
That paper showed Covid increased the chances of developing myocarditis 18-fold, roughly in line with the new CDC study.
The CDC in June concluded that the benefits of Covid-19 vaccination outweigh the risks of vaccine-caused myocarditis, even in the most at risk group.
The new study’s authors wrote that the new data backed up that claim.
The benefits of vaccination increase when community transmission of Covid is high and the chances of contracting the disease are elevated.
This is currently the case in the United States, which is experiencing its second biggest wave to date thanks to the Delta variant.