The plot of the discovery of the omicron variant had been written for months. The first chapter of the story tells that the low vaccination coverage in many parts of the globe increases the risk of new forms of the virus emerging. The second says that these variants can be more contagious, virulent or escape the protection conferred by vaccines. The end result is a situation in which they could return, as has happened, drastic measures already seen in the first months of the pandemic, such as the closure of borders or the suspension of flights.

The development of the plot seen in recent days, however, may have skipped the second part, some experts warn. “Borders have been closed before the data arrived to justify it,” laments Fernando González Candelas, professor in genetics at the University of Valencia and researcher at the Fisabio Foundation. “It was all a bit hasty. With the mutations detected, there are reasons to consider the new variant of interest. You have to monitor it and follow its evolution. But what is of concern has yet to be proven. Science is based on the analysis of data that allow us to draw solid conclusions and we still don’t have them here, ”he says.

Not all specialists, however, are of this opinion. “I don’t think we were too hasty. In fact, it is already outside the countries of South Africa. The risk is very high and it is necessary to adopt measures as soon as possible to stop its spread ”, defends Santiago Moreno, head of infectious diseases at the Ramón y Cajal Hospital (Madrid). The Netherlands announced on Tuesday that it had detected the new variant in samples taken between November 19 and 23, up to six days before South Africa reported its discovery. South African researchers have for now identified samples dating back to November 14 with the new form of the virus.

The WHO has harshly criticized the restrictions imposed by the governments, which it accuses of punishing South Africa precisely for having been diligent in detecting and warning about the new variant, although its reports describe the global risk it poses as “very high”. .

The experts consulted agree that it is not surprising that the new variant has emerged in the least vaccinated continent on the planet – barely 11% of the population has completed the pattern, 29% in South Africa, according to the OurWorldInData repository – although for now it is not known exactly where or when it arose. If its origin is located in South Africa, it is because this country has a remarkable sequencing capacity, much greater than that of its surroundings, which may have allowed it to first identify a new form of the virus that has been circulating for some time.

“Mutations are errors in the RNA copy that occur when the virus replicates and, therefore, the probability that they appear is related to the global number of times it does. The countries of South Africa have low coverage, which favors circulation. Furthermore, they have a high prevalence of patients with HIV-weakened immune systems, who do not always receive adequate treatment. This favors chronic or longer infections, during which the virus replicates many more times. The overall effect is that the risk of new variants emerging in these areas is greater, ”says Moreno.

The World Health Organization (WHO) declared last Friday a variant of concern, baptized as omicron, to the one initially called B.1.1.529. In a document, the agency assures that it did so based on the “high number of mutations detected [más de 30], which may have an impact ”on the way“ in which the virus spreads or the severity of the clinical pictures it causes ”, something that, however,“ is not yet clear ”, can be read in the text.

The first information that points to greater transmissibility is based on the speed with which it became dominant in a province of South Africa and has begun to spread to other areas of the country. “Although these are very preliminary data, they suggest that it is more contagious than the delta,” says Moreno. The implications are important: “If the percentage of the immunized population needed to get closer to protection grew with the delta of 70% initially estimated to more than 80%, with the omicron this can reach 90% or more”, estimates the head of infectious diseases of the Ramón y Cajal.

González Candelas is more cautious: “The only data available so far are from a province with a very low incidence and with cases associated with one or two outbreaks. This, in relative terms, can lead to an inappropriate assessment of the information ”. All the experts agree that, with the known data, it is not possible to affirm that the new variant causes more serious clinical pictures or that it is capable of eluding the defenses generated by the organism after the vaccine or having passed the infection.

Ignacio López-Goñi, professor in Microbiology at the University of Navarra, admits that “the accumulation of mutations is worrying because there are many and, in addition, among them there are some that we have already seen that increased the transmissibility of other variants”. “But, on the other hand, we also don’t know anything conclusive about the biology and epidemiology of omicron. One thing is the number of mutations and another is the effect they can have, because some can be compensated for with others and ultimately not have relevant biological effects. It could even be the case that this variant is more transmissible, but that it produces a milder disease, which would not be bad news ”, he explains.

Angelique Coetzee, the South African doctor who helped focus on the new variant, explained that the first cases “have been very mild”, although all of them were young and healthy people. An advanced information by Bloomberg, based on Official data affirms that one in 10 admitted in recent dates in Tshwane, the epicenter of the omicron in the country, is two or less years old. It is a similar percentage to that registered in the first moments of the delta variant, although higher than that of the first two waves suffered by the country. This information is too preliminary to draw conclusions, experts agree.

For López-Goñi, the problem is not so much that the WHO rushed to declare the new variant as a concern, but in the “excessive” reaction of many countries. The European Union, the United States and more than 20 countries suspended flights with southern African countries and others, such as Japan and Israel, have opted for the complete closure of borders. A situation that has been defined this Monday by the Minister of Health of the Generalitat of Catalonia as “panic in the Western world.”

The loss of efficacy of vaccines is one of the biggest concerns you hover over the emergence of each new variant. Pfizer-BioNTech and Moderna have already announced that they are working on adapting their serums in case a new dose adapted to omicron is necessary, a process that the European Medicines Agency (EMA) has shown willing to facilitate, but for what would be required three to four months.

“We do not have data that allow us to affirm that all this is going to be necessary, at least for now,” says González Candelas. “We know that there are mutations in the spicule, but it is very difficult to deduce from that without data on the ground that it will decrease the effectiveness. In addition, here proportionality comes into play. If we start from an effectiveness that exceeds 90%, even if the vaccine escape can be increased somewhat, it would be necessary to assess whether the effort involved in adapting vaccines, revaccinate the population … is justified, ”he concludes.