Can the Delta Plus variant turn the tide of the pandemic?

Mass and complete vaccination is proving to be the best weapon against COVID-19, which must be complemented with other protective measures. But the appearance of a subvariant of the Delta mutation, known as Delta Plus, put the world’s health authorities on alert. Still, the elements they have experts so far show that existing vaccines are still effective in preventing serious cases and death.

Scientists have warned that the way the virus can mutate is with infections, so preventing more and more people from becoming infected is what will stop the appearance of new SARS-CoV-2 mutations.

The Delta Plus variant, technically known as AY.4.2, is a subtype of the Delta mutation of the SARS-CoV-2 coronavirus. It was first detected in the UK last June and gradually spread across the country. Although it does not have an official name, it could soon be called the “Nu variant,” according to the Greek alphabetical system for naming new strains of the virus. Experts estimate that it first emerged in London or the southeast of the country, but there is still no clear evidence of its origin.

On October 21, the UK Health Security Agency (HSA) designated AY.4.2, a mutation of the Delta B.1.617.2 strain, as an “investigational variant”.The Delta variant was first found in India in October 2020 and its lineage is found in approximately 70% of all sequenced samples. Both Delta and Delta Plus have been seen to have higher infectivity than the original Wuhan virus.

The Centers for Disease Control (CDC) stated that “there is no evidence that this variant impacts current vaccines and therapies.”For his part, the former commissioner of the food and drug regulatory agency (FDA), Scott Gottlieb, stated that to know the real risk of this variant “More research is needed” and that it may be “slightly more transmissible”, up to 10% more, according to some sources without that suppose a reason for the alarm.

Immunologist Jorge Carrillo, who is a member of the Spanish Society of Immunology and a researcher at the IrsiCaixa de Badalona, sent a reassuring message since so far the action of this subvariant is under study and vaccines continue to be effective in fighting the disease. In this sense, he recalled that the so-called Brazilian (Gamma) and South African (Beta) variants showed greater infectivity, and even so they were not prevalent worldwide.

For his part, François Balloux, a specialist in genetics, evolution, and computational biology at University College London considered that it is not comparable with the emergencies of Beta or Delta variants, which, according to some estimates, were 50% more transmissible than their predecessors. In the case of Delta Plus, it is only “potentially a small increase in transmissibility that would not have a comparable impact on the pandemic”, estimated.

An article recently in the journal Cell Reports, it is concluded that both the Delta variant and the Delta Plus subvariant infect lung cells more effectively than the original virus. The same work found that one of the four antibodies used to treat COVID-19 was not effective against Delta, and Delta Plus was even resistant against two therapeutic antibodies.

Still, the WHO Executive Director Mike Ryan noted that vaccination achieved a decrease in the number of COVID-19 infections, despite the aforementioned.

Carrillo recalled that vaccines do not immunize 100% but protect against contracting a serious infection, hospitalization, and death from this infection. Then, he reiterated the recommendation of the entire scientific community regarding the need for all eligible people to be vaccinated because existing inoculants “are effective against any variant currently in circulation.” He also asked to maintain hygienic measures carried out in the last two years, especially social distancing, hand washing, and the use of chinstraps, especially in closed places.

The expert highlighted that the Delta Plus subvariant is considered as “Variant of interest” by the United Kingdom, this means that it is a variant that is being studied more carefully to verify if it is ultimately more contagious and if vaccines are resistant to it, although he stressed that today it is investigating.

The subvariant of the Delta strain, which is on the rise in the UK, is now on the radar of the World Health Organization (WHO) which fears it may be up to 15% more infectious than its already highly infectious predecessor. virulent. As of October 25, more than 26,000 cases of the branch have been reported in 42 countries, said the UN agency, which currently dedicates an entire segment of its weekly epidemiological report to the new strain.

It has not yet been determined whether it is more virulent or dangerous than the original. For the most part, Delta remains the dominant variant due to its high transmissibility and ability to glide through the protective coating of vaccines. While it has not been shown to be significantly more transmissible, the secondary attack rate of AY.4.2 (the probability of an infection occurring in a group of people) in UK domestic settings is 12.4%. For the Delta variant, it is 11.1%. This means that in the same household, there is a greater chance that an infection will spread if you have the AY.4.2 mutation.

There is also no clear indication in the UK that AY.4.2 leads to more serious illness, based on initial analyzes based on emergency visits and hospitalizations. “However, these analyzes do not adjust for crucial factors that may influence results, such as age and vaccination status, and should be interpreted with caution,” the UK HSA noted on October 22.

This also means that the reasons for the increased transmissibility of the mutation are unclear: is it the nature of the group in which these infections are increasing (elderly or unvaccinated) or the region of their high prevalence? However, it is important to note that infections spread faster and cause serious illness in unvaccinated or partially vaccinated populations, even with the Delta variant, and vaccines remain highly effective in preventing hospitalization and death.

Scientists at Northumbria University in Newcastle involved in variant surveillance say that “it is not yet clear whether AY.4.2 is actually more transmissible because very little is known about its mutations.” And they pointed to the “founder effect” as an alternative explanation, this is when a subset of the virus separates from the general viral population and then reproduces in isolation. In the area where the separate viruses are found, all subsequent viruses will therefore be descendants of this subset.