“The big concern is that the next variant to emerge, just a few potentially mutations away, could eventually evade our vaccine.” They are statements of Rochelle Walensky, Director of the US Centers for Disease Control (CDC). His words, to justify the CDC’s decision to recommend the indoor mask again for those vaccinated, after the rise of the delta variant, warn of the great fear of the pandemic, that a strain will emerge that completely bypasses the immunity induced by vaccination. Almost no expert in Spain rules it out, although they put three certainties ahead. One: vaccines are still very effective in greatly reducing the risk of serious illness and death from COVID-19. Two: No country should be left behind in vaccination. And three: if an escape strain emerges, vaccines can be quickly redesigned to be effective against it, especially mRNA vaccines, such as those from Pfizer and Moderna.
The scientific debate centers on a specific question: Are there limits to how much SARS-CoV-2 can evolve to escape antibodies? The professor of Parasitology Rafael Toledo, from the University of Valencia, wrote a few weeks ago in “The Conversation” an article in which he charged against the “barrage of apocalyptic prophecies” on the variants. In it he pointed out that mutations in the “S” protein, the “key” that the coronavirus uses to enter the “lock” of the cell, the ACE2 receptor, can affect the viability of the virus. “When we make a copy of a key and it does not fit well, we file the teeth and we improve its complementarity with the lock. But these changes have to be limited, because if we make too many the key loses complementarity and is useless –explains Toledo in the article–. Changes can occur in S, but to escape the immune response it would need so many changes that it would lose its complementarity with ACE2 and, therefore, its viability ”.
“That an escape variant comes out is inevitable”, says Benito Regueiro
Few dare to take this hypothesis as safe. Asked about it by FARO in a scientific colloquium, the head of Microbiology at the Álvaro Cunqueiro de Vigo Hospital, Benito regueiro, pointed out that the fact that “a variant of vaccine escape is inevitable, it is what the virus has to do.”
Professor of Microbiology Ignacio López-Goñi, from the University of Navarra, pointed out in an interview with FARO that “it is very difficult to make predictions.” Although coronaviruses mutate less than the AIDS and flu viruses, he said, “they can mutate and recombine,” and “this moment, with many half-vaccinated people, is delicate, because variants may continue to appear that give us some fright” .
In another interview, the immunologist Africa González pointed out that a problem of letting the virus circulate among young people “is the generation of mutations, so that variants arise that can escape immunity, either after having developed the infection or after vaccination.” The researcher from the University of Vigo stressed that this pandemic must be understood as something global: “If there are areas in the world with a high rate of infection, the virus will mutate.”
In this sense, Benito regueiro He recalled that “in a day there may be 385 million infected in the world. That means there are 10 to 21 copies of the virus, ”which multiplies the chances of problematic mutations appearing.
The head of the infectious diseases service of the Hospital del Mar in Barcelona, Robert Güerri, has also been concerned about the possibility that the virus may end up escaping from vaccines if it continues to mutate, and has warned that it will mutate more the greater the lack of control of infections.
Researchers Eric Topol (The Scripps Research Institute, USA) and Roberto Burioni (San Raffaelle University, Milan, Italy) signed an article in “Nature Medicine” in which they highlighted the need to “achieve global containment of SARS-CoV-2” as soon as possible to avoid further substantial evolution, a term which generally connotes slowness but has been happening rapidly ”.
It is what the Galician researcher in Houston (USA) Sonia Villapol he has called “The Pandemic of Unvaccinated People.” The professor at the Houston Methodist Research Institute recalls in a recent article in “El Progreso” that “vaccinated people can also get infected”, and that “every time the infections increase, even among vaccinated people, we are giving the virus the opportunity to mutate and emerge new, more transmissible and virulent variants ”.
Amos Garcia, president of the Spanish Society of Vaccination, said on TVE that “as long as there are still cases, new variants will continue to appear, some of which will be more resistant to current vaccines.” If this happened, the laboratories would adapt their vaccines, although this would require revaccination. In this sense, the co-founder of BioNTech, Özlem Türeci, highlighted in a recent interview with “La Nueva España” –of the same FARO communication group–, that in August the tests of the new Pfizer-BioNTech vaccine would begin to better adapt to the delta variant. Pfizer continues to insist on the convenience of third doses.
Virologist and Research Professor Miguel Angel Jiménez Clavero has pointed out that, although vaccines protect against the delta variant, this “is not far from being able to give a scare”. However, his colleague Jose Manuel Jimenez, an expert on coronavirus at King’s College London, told FARO a few weeks ago that, although “It is not impossible “that a variant that is resistant to vaccines may appear,” the probability is not very high, especially considering that so far none of the identified variants is resistant, “he stressed. “In addition, we are seeing the same mutations appear independently in different parts of the world and that means that the options available to the virus to optimize infection and transmission could be limited,” he said.
Another reason for optimism is that not only antibodies (humoral response) count in the immune response, but also T lymphocytes (cellular response).
In any case, it is advisable not to forget what the microbiologist advised Benito regueiro: “Viruses are intelligent machinery, they originated 4,000 million years ago,” he recalled in a discussion in Vigo. When viruses began to develop, the Moon did not even exist. They have a learning capacity far superior to ours. We see variants that have learned from confinement how to attack us ”.
“There are vaccinated people infected with delta with the same viral load as those not vaccinated”
Another warning from the United States that causes concern and debate among the scientific community is that of the immunologist Anthony Fauci, which has warned that in vaccinated people who have been infected with the delta variant of the coronavirus, a viral load has been found equal to that of the unvaccinated who infect. “When we see the level of virus in the nasopharynx of a vaccinated person who has a delta infection, it is exactly the same level of virus as that of an unvaccinated person who becomes infected,” he told the US channel MSNBC. According to this world-renowned scientist, these “very strong data” have caused the CDC to change its criteria, which has once again recommended the indoor mask for those vaccinated as well.
The journal Nature published on Monday an article in which it pointed out that several studies had confirmed that vaccines reduce the transmission of SARS-CoV-2 by more than 80%, but these works were carried out before the delta variant, much more transmissible, became prevalent. Much remains to be investigated.