A study from Israel indicates that the Coronavirus vaccines no longer work properly against the South African variant B.1.351. Does the mechanism of antigenic sin apply?
TEL AVIV – Do existing vaccines also protect against virus mutations? This appears to be the case for the British variant B.1.1.7, which almost completely displaced the “wild type” of Sars-CoV-2 in several countries and also in Germany; With at most a small loss of efficacy. The situation differs with variant B.1.351, which first appeared in South Africa.
Then there is bad news from Israel: According to a recent study by Tel Aviv University and the Universal Health Organization – the largest health insurance company in Israel – people who were vaccinated were infected eight times more than those who had not been vaccinated in the south. The African alternative. However, the numbers are very small overall, as this virus strain rarely spreads in Israel, 90 percent of infections there are caused by the British alternative. The study was only published after it was previously printed on medRxiV and has not yet been reviewed.
Coronavirus vaccination protection is not always effective for the South African Corona variant
In Israel, 4.9 million people – about 53 percent of the population – received two doses of the vaccine. Only mRNA vaccines are injected, and most of them come from Biontech / Pfizer, which is a smaller fraction of Moderna. In order to study it, the research team examined samples from 150 people who had tested positive for the Coronavirus and were partially asymptomatically infected, but also partially sick, although they had either already received the first vaccination or even two vaccinations.
The Times of Israel quoted the director of the study, Adi Stern, as saying: “Based on the picture in the general population, we were expecting to find one case of the South African type, but we saw eight cases.” Compared to the original virus strain and the British variant, the South African variant is able to penetrate vaccination protection. Ran Palser, director of research at the public health organization Clalit, said the study was “extremely important”, as it was the first to draw on data from the real world.
As early as the end of March, scientists from Ben-Gurion University in the Negev found in laboratory tests that the vaccine from the Biontech-Pfizer was not able to completely neutralize the South African variant and was also less effective against strains that had characteristics of both the British and who also carried the southern variant. African.
The study from Israel can be found at www.medrxiv.org
The Corona study with “real world data” comes out worse than laboratory tests
This research team worked with samples from people who survived a natural infection, as well as samples from people who were fully vaccinated and with the first dose for their study. This substance was exposed to so-called pseudo-corona viruses in a petri dish. At that time, the result appeared to be low but still effective against the South African alternative. This was higher than after surviving a “wild type” SARS-CoV-2 virus.
The results of the current study with “real-world data” appear worse by comparison. Ran Pleaser of the Clalit Health Organization stresses the importance of being vigilant. This includes continuing to wear masks indoors and practicing social distancing. Epidemiological monitoring and systematic sequencing of virus material in corona-positive samples are also essential.
Until now, the South African alternative was scarce in Israel. Study leader Addy Stern assumes she is responsible for only about one percent of injuries. No other mutations were found in the study. Researchers believe that conditions in Israel are more favorable to the British than the South African alternative.
Astrazeneca vaccine hardly protects against the South African variant
Weeks ago, a study from South Africa showed that the Astrazeneca vaccine, which relies on a different technology as a vector vaccine, barely protects against the South African variant. Therefore, vaccination with the vaccine was stopped in South Africa.
The thing most disturbing about the Israeli study is the fact that people who were vaccinated were more likely to be infected with the South African variant than those who were not – even if there were only eight cases in total. The study also did not provide any indication of whether people who had been vaccinated with B.1.351 had contracted Covid-19 and how severe the disease was. Could so-called “antigenic sin” play here? There is already separate scientific work devoted to this theory regarding Sars-CoV-2. It is important to emphasize that antigenic sin is a theory, not a proven fact.
Is antigen sin valid? The immune system is based on an old version of the antigen
Assumption: If the immune system has already been infected with a virus and then encounters a new variant, it can tend to form antibodies only against structures familiar to it from the original pathogen. According to this theory, the immune system will always produce copies of the antibodies against this antigen, which it recognized upon first contact, and will not be able to adapt properly. The principle can also be applied to grafting. In the worst-case scenario, this could be harmful when a person is exposed to a new variant of the virus because the immune system is focused on an old version of the antigen. In the case of SARS-CoV-2, this target structure is a spike protein; All vaccines are based on the original version of this protein.
Now, however, mutations of new viral variants are occurring specifically on this spiky protein, in the largely South African variant of the British protein. American immunologist Matthew Woodruff of Emory University in Atlanta writes about this problem in the British science journal The Conversation. He is concerned that vaccine updates that have been adapted to new virus strains may be less effective in people who have already received the first vaccinations. In this case, the immune memory could interfere with the development of a good immune response to the adapted vaccine. The scientific world will have to deal with this emerging problem and work on “complex” vaccines that work against many strains of the virus. Vaccines are already being researched for influenza. Knowledge from this should, according to the US immunologist, be transferred to Sars-CoV-2 immediately. (Pamela Durhofer)