Since the beginning of December last year, the whole country began to stop carrying out nucleic acid for all employees, and many people have experienced secondary infections this year. After the country released the "Implementation Plan for the Second Dose of Booster Immunization of the New Coronavirus Vaccine", it also announced that it was now possible to start receiving the "4th dose" of the new crown vaccine. But research has differed as to whether a prototype SARS-CoV-2 booster vaccination can help induce the production of antibodies against the Omicron variant.
Recently, researchers from the First Affiliated Hospital of the University of Science and Technology of China conducted a SARS-CoV-2 infection survey and collected blood samples on 750 Chinese residents, and found that booster vaccination of the prototype vaccine can help patients produce higher IgG antibodies against the Omicron variant. The study, titled "A survey and antibody test following the surge of SARS-CoV-2 Omicron infection in China," was published in Medrxiv.
Since its spread, SARS-CoV-2 has developed many variants, such as Alpha, Beta, Delta, Omicron, etc. At present, the Omicron variant has become the main epidemic strain, including the Omicron branch BA.5, BF.7, XBB and so on. More than 30 spike(S) protein mutations and 15 S protein receptor binding domain mutations have been identified in the Omicron variant, which induces escape neutralization activity of most identified anti-SARS-CoV-2 neutralizing antibodies.
Is vaccination inferior to getting Omicron once?
Many people think that once infected, antibodies against the virus will be produced once and for all, which is very wrong. Experts from the Chinese Center for Disease Control and Prevention said: Although the currently circulating Omicron strain is less pathogenic than other variants circulating in the past, there is still a risk of severe disease and death; And the risk of severe disease and death is felt at all ages. And unvaccinated people are at higher risk of hospitalization, severe disease, and death than those who have completed full vaccination or booster shots. This risk can be reduced by vaccination.
Herd immunity may not be effective in preventing infection with highly mutagenic Omicron variants
Several vaccines have been developed to control infection and transmission of SARS-CoV-2, including messenger RNA (mRNA)-based vaccines, viral vectors, recombinant proteins, and inactivated SARS-CoV-2 vaccines.
1. Booster doses of inactivated SARS-CoV-2 vaccines result in a significant increase in neutralizing immune responses against prototype SARS-CoV-2 and incompletely evaded Omicron variants.
2. Repeated vaccination with inactivated virus vaccine may evoke a strong immune response against the prototype strain, while it suppresses the immune response against the new Omicron variant even with the Omicron BA.5 vaccine booster.
Thus, current herd immunity may not be effective in preventing infection with highly mutagenic Omicron variants.
Vaccination with the prototype SARS-CoV-2 vaccine is capable of producing antibodies against the new variant
Researchers investigated 750 people in Hefei, Anhui Province, China, for SARS-CoV-2 infection and collected blood samples from 636 people. For those surveyed, the median age was 32 years, of which 308 were women.
Of the 636 people, 441 were confirmed infected by antigen or nucleic acid testing, 142 tested negative twice, and 53 were not tested by the time blood was taken. Men and women test positive at similar rates. The percentage of infected patients increases with age. The 96% of people who are fully vaccinated are as follows:
2 doses of inactivated SARS-CoV2 vaccine (10.53%);
3 doses of recombinant protein vaccine (4.09%);
2 doses of inactivated SARS-CoV2 vaccine and 1 dose of booster dose of inactivated SARS-CoV2 vaccine (57.55%);
2 doses of SARS-CoV2 inactivated vaccine and 1 dose of recombinant protein vaccine booster dose (12.42%);
2 doses of inactivated SARS-CoV2 vaccine and 1 booster dose of AdVs vaccine (1.26%);
2 doses of mRNA vaccine (0.63%);
3 doses of mRNA vaccine (0.16%);
4 doses of vaccine (8.49%)
Surveys into timing and infection in these populations have found that booster doses of the vaccine may protect people from SARS-CoV-2 infection. Next, the researchers tested levels of IgG, IgA, and IgM antibodies specific to the prototype SARS-CoV-2 receptor-binding domain.
The results showed that the IgG of infected patients was significantly higher than that of uninfected patients, and the IgG level of severe patients was higher than that of mild patients, and further analysis found that the IgG level of patients taking drugs was higher than that of patients treated with non-drug treatment. Vaccination is one of the most effective ways to control the spread of SARS-CoV-2. Therefore, the researchers analyzed the IgG levels of people who received the last dose of the vaccine on different days.
It was found that IgG levels increased over time over 30 days and infection led to higher IgG levels.
Thus, the prototype SARS-CoV-2 booster vaccine has shown a high ability to induce IgG antibodies against the proto-SARS-CoV2, while how the proto-SARS-CoV-2 booster vaccine can help protect against Omicron infection remains unknown.
To do this, the researchers collected plasma from 41 infected patients and 15 uninfected people to test antibody levels against different variants of SARS-CoV2. It was found that individual antibody levels against Omicron BA.5, BF.7, and XBB 1.5 were highly positively correlated with antibody levels against proto-SARS-CoV2.
In addition, antibody levels against proto-SARS-CoV2 can represent antibody levels against Omicron BA.5, BF.7, and XBB 1.5 in both infected and uninfected individuals, and infection with Omicron induces high levels of antibodies against the proto, Omicron BA.5, BF.7, and XBB 1.5 variants in fully vaccinated patients.
summary
The study found that the last booster vaccine protected people from SARS-CoV-2 about 3 weeks after rapid pandemic infection. IgG levels are higher in severe disease than in mild disease. In addition, the 4th booster dose induces comparable antibody levels in 2 or 3 doses of the prototype Omicron BA.5, BF.7, and XBB 1.5 variants in infected patients, and induces higher antibody levels after infection.
In summary, booster vaccination of the prototype vaccine can help patients develop higher IgG antibodies against the Omicron variant, which recalls a strong immune response against the prototype strain. Be sure to get vaccinated when it's time to get it!
Source: Life Sciences Frontiers