South African researchers updated laboratory study data on Saturday, saying two doses of the Pfizer/BioNTech vaccine were only 22.5 percent effective in preventing symptomatic infections with the new coronavirus variant " Omi kerong " , but still able to stop serious disease.
The study, led by the African Health Institute in Durban, provided additional data for a small study released Friday. A previous small study of serum samples from 12 participants found that "Omi kerong" resulted in about 41-fold reductions in neutralizing antibody levels from two doses of the Pfizer vaccine compared to the original strain of the new coronavirus.
Alex Sigal, head of the laboratory at the African Institute of Health, said: "This essentially undermines the vaccine's ability to prevent infections. ”
Officials from the UK Health Safety Agency (UKHSA) also said on Friday that two unpublished UK studies and three international studies showed that the vaccine's ability to neutralize the "Omilon" variant was reduced by 20 to 40 times compared to the original strain.
According to a recent study released by the Peking University research team, after analyzing the escape of neutralizing antibodies in 247 viral spike protein RBD (receptor binding region), it was found that more than 85% of the existing COVID-19 neutralizing antibodies can be escaped by "Omi Kerong". In the serum of covid-19 survivors, almost all neutralizing antibodies are targeted at spike proteins.
However, in response to the effectiveness of vaccines, WHO scientists believe that the decline in neutralizing antibodies does not mean that the effectiveness of vaccines and the like declines, because the human immune system is very complex. SOUMYA Swaminathan, WHO Chief Scientist, said: "The body's immune system has T cells and also memory B cells, and it is still too early to conclude that the effectiveness of the vaccine has decreased significantly based on the reduction of neutralizing antibodies. ”
At the same time, several international studies have demonstrated that vaccination with vaccinators can provide important protection against "Omi kerong". Israeli researchers said on Saturday they found that after the third dose of the Pfizer/Bynteco vaccine, neutralizing antibody levels increased by about 100-fold, providing important protection against "Omilon."
The Israeli study was conducted in collaboration with the country's Sheba medical center and the Central Virology Lab of the Israeli Ministry of Health. The research team compared the serums of 20 people who had received two doses of the vaccine 5-6 months earlier with the same number of people who had received the booster vaccine a month earlier.
The results of the study against the live virus showed that the serum of people who received two doses of vaccination 5-6 months ago had little ability to neutralize "Omilon", but produced some immune response to the "Delta" variant; while the serum neutralization antibody levels of those who received the booster vaccine increased by about 100 times.
Gilli Regev-Yochay, Director of the Infectious Diseases Division at Sheba Medical Centre in Israel, said: "This is good news because with the vaccination of the booster, the protective effect of the vaccine has increased significantly. Although the enhancer's protection against Amikeron is still about four times lower than that of the Delta strain. ”
The results of the study in Israel are similar to those released earlier this week by Pfizer and Byntec. But Israeli research uses real live viruses, while companies use bioengineered "fake viruses" with iconic mutations of "Omicron."
According to a preliminary UK data released on Friday, the effectiveness of the vaccine against "Omiljung" can be immediately increased to 70% to 75% for people who receive two doses of the AstraZeneca or Pfizer/Bainteco vaccine.
But researchers are still unsure how long this protective effect of boosting the vaccine will last. In response, Pfizer CEO Albert Bourla said: "How long the three-shot vaccine can provide protection for the mutant strain is still to be verified by real-world data. But because viral variants can produce immune escape from vaccines, people may need to get a fourth dose of the vaccine earlier than expected. ”
Pfizer and Baintec have said they will develop a vaccine specifically targeting the "Omikeron" variant by March next year, which will help the vaccine provide specific protection. But given that new variants may emerge in the future, the company is closely monitoring whether the vaccine needs to be adjusted.