Subvariants of Ómicron BA.4 and BA.5: WHO explained whether they are more severe or more transmissible than the previous ones

While the number of cases of people with COVID-19 and deaths have recently been reduced, the World Health Organization (WHO) is closely monitoring the evolution of coronavirus and the emergence of variants and their sublineages. Ómicron is still the dominant one in the world, and recently its sublinages BA.4. and BA.5 have been detected, which according to the United Nations health agency do not imply that they generate more serious cases or are more transmissible than the other subvariants that have already advanced in their circulation.

Last week there were the lowest number of deaths from COVID-19 since the first days of the pandemic, according to WHO. However, he warned that in some countries there are still “serious peaks” in cases, a situation that puts pressure on hospitals.

As the coronavirus continues to evolve, we must not “lose sight” of its changes. The director of the global health agency, Tedros Adhanom Ghebreyesus, called attention to governments to the need to increase the number of tests and sequenced samples so that scientists can keep track of existing variants and identify new ones as they emerge.

He stressed that a decrease in the number of cases and deaths does not necessarily mean a “lower risk”. And he pointed out that if the number of tests to detect the disease is reduced, the “ability to control its tendencies” is compromised.

“There are currently a number of Ómicron lineages that we are following closely, including BA.2, BA.4 and BA.5 and another recombined that has been detected, composed of BA.1 and BA.2 ″, said Dr. Ghebreyesus.

Variants BA.4 and BA.5 have been reported in several countries, including South Africa and some European nations, reported the Organization's lead epidemiologist, Dr. Maria Van Kerkhove. “So far there are less than 200 sequences available and we hope that this will change (...) We are following (the virus) very closely to see if there is any spike in case detection, but (so far) we haven't seen any changes in epidemiology or severity,” he said.

For his part, the agency's director of emergencies, Michael Ryan, warned that as long as the virus continues to evolve, the world “cannot afford to lose sight of it.” “At this point it would be very unwise to assume that fewer cases mean absolute risk reduction. We are happy about the decline in deaths, but this virus has surprised us before, it has caught us off guard,” he warned.

“We need to do our job and keep track of this virus as best as possible, while people get back to living their lives as normally as possible,” Ryan explained. For her part, Dr. Soumiya Swaminathan, the scientific director of the Organization, warned that lineages and recombinations will continue to appear, and that the world must continue to invest in improving tools such as new vaccines.

“We need to prepare ourselves for the possibility that the virus will change so much that it is capable of avoiding the current immunity capacity,” he said. The coronavirus pandemic is still a global public health emergency. The WHO director also highlighted that the virus has become more transmissible over time, especially for unprotected and unvaccinated people who lack access to health care and antiviral drugs.

“The best mode of protection is to get vaccinated and booster doses when recommended. Keep wearing masks, especially in busy indoor spaces. And for enclosed spaces keep the air current by opening windows and doors, and invest in a good ventilation system,” he asked.

He also recalled that the Emergency Committee of the International Health Regulations - charged with assessing the global state of the COVID-19 situation - unanimously agreed this week to continue considering the pandemic a global public health emergency. “Instead of letting your guard down, this is the time to work even harder to save lives,” Tedros said of the Committee's decision.

On 11 April, South African scientists announced the detection of the two new sublineages of the Ómicron variant, BA.4 and BA.5. It was disseminated by Tulio de Oliveira, who heads genetic sequencing institutions in that country. His group was the one who announced the detection of Ómicron BA.1, which produced explosive waves since November last year in the world.

The lineages have been christened BA.4 and BA.5, he said via text message and in a series of tweets. However, according to de Oliveira, lineages have not caused a peak of infections in South Africa and have been found in samples from several countries. “Given the few infections, hospitalizations and deaths in South Africa, we are alerted to the continuing evolution, but not worried,” de Oliveira said via text message. “All laboratory science on neutralizing the virus and vaccines is already in place and we are strengthening genomic surveillance,” he said.

Sublinages BA.4 and BA.5 have also been found in samples from Botswana, Belgium, Germany, Denmark and the United Kingdom, de Oliveira said. The two lineages have similar mutations in their spike proteins, the part of the virus that helps it attach to human cells, to the BA.2 sublineage, which appears to be more infectious than the variant found in November. They also have some additional mutations, he said.

In addition, the head of WHO again this week recalled the inequality in the distribution of vaccines. “Reducing the gap in vaccine distribution is the best way to increase the population's immune capacity and protect it against future waves,” he stressed and highlighted the need to establish a new pandemic treaty for the future. “A new agreement on pandemics is our best collective defense against known viruses and, of course, against the next disease X,” he concluded.

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