Pfizer and AstraZeneca’s new coronavirus infection (COVID-19, Corona 19) vaccine is safe and effective in immunization, a study has found. Research has also shown that the immune effects of mRNA vaccines such as Pfizer and Moderna can last for up to several years. As a result, it is possible to flexibly respond to vaccination plans, such as increasing cross-inoculation when supply of certain types of vaccines is not smooth.
○ mRNA vaccine immunity effect, maintained for up to several years
As the COVID-19 epidemic has passed more than a year and the number of people who have completed the vaccine has increased, research has been ongoing in the academic community to see how long the immune effect of the COVID-19 vaccine will be maintained. The duration of vaccine immunity is directly related to booster shot vaccination and the supply and demand of vaccines.
A research team led by Ali Elevedi, an associate professor of pathology and immunology at Washington University School of Medicine in St. Louis, USA, investigated the duration of immunity in 14 people who had completed vaccination with the Pfizer vaccine. It was announced on the 28th.
The researchers examined lymph node cell samples 3, 4, 5, and 7 weeks after receiving the first dose of the Pfizer vaccine from 14 people, respectively. In 10 of these patients, lymph node cell samples were taken 15 weeks after vaccination.
When the COVID-19 vaccine is administered, a special structure called the germinal center is formed in the lymph nodes. The germinal center activates memory B cells to recognize the virus and is considered a key factor in the formation of immunity as it makes antibodies.
According to the paper, in lymph node cell samples of 14 people who received the first dose of Pfizer vaccine, all germinal centers involved in antibody production were formed three weeks later. In addition, even after 15 weeks, the germinal center, including memory B cells, was confirmed in 8 of 10 patients. In general, as the germinal center peaks after 1 to 2 weeks and then decreases, maintaining the germinal center for about 4 months means that the immune effect can last that long.
“The germinal center is a key region where a continuous immune response is made, and the longer the germinal center is retained, the longer the immunity is maintained,” Elebedee said in a press release at Washington University Medical School in St. Louis. “Even 15 weeks after the first dose of the Pfizer vaccine, the immune system is maintained.” The germinal center still did not decrease, meaning that the immunogenic effect of the mRNA vaccine could be maintained for up to several years.”
○ 1st Pfizer – 2nd AstraZeneca, high immunity effect
The BBC reported on the 28th (local time) that when the first Pfizer vaccine and the second AstraZeneca vaccine were administered at 4-week intervals, antibody formation and T-cell response were higher than when the AstraZeneca vaccine was given both times. did.
This was based on the findings published on the 25th of SSRN, an online pre-publication site of the medical journal ‘The Lancet’ by researchers at Com-COV, Oxford University, UK, who have studied the effect of cross-vaccination of the COVID-19 vaccine. This study is the largest cross-inoculation study published so far.
The research team divided 830 adults 50 years of age and older into 8 groups and divided the 1st and 2nd AstraZeneca, 1st AstraZeneca, 2nd Pfizer, 1st and 2nd rounds, respectively, at intervals of 28 days (4 weeks) and 84 days (12 weeks). Pfizer, 1st Pfizer and 2nd AstraZeneca were vaccinated. Their average age was 57.8 years, and 45.8% were female.
A month later, the researchers investigated the antibody production rates in the blood of eight groups, and found that the first dose of Pfizer vaccine and the second dose of AstraZeneca vaccine had a higher antibody production rate than those who received AstraZeneca first and then Pfizer.
In addition, the cross-vaccination of AstraZeneca and Pfizer vaccines showed a significantly higher rate of antibody formation than those in which two doses of AstraZeneca vaccine alone were administered, regardless of the order. However, the highest rate of antibody formation was observed in the group that received two doses of Pfizer vaccine alone.
According to the BBC, Oxford University professor Matthew Snape, who participated in the study, said at a press conference on the same day, “It is more useful to cross-vaccinate one dose each with AstraZeneca and Pfizer vaccines in order to increase immunity than to get both doses with AstraZeneca vaccine alone. ” he said.
In the UK, more than 80% of adults have completed their first dose of the COVID-19 vaccine, and 60% have completed their second dose. However, as the number of confirmed cases surged again due to the recent delta mutant virus epidemic, the British government is also considering a ‘boost shot’ before winter, when the activity of the Corona 19 virus is active in time to maximize the immune effect.
Professor Paul Hunter at the University of East Anglia told the BBC, “The biggest concern right now is whether a person who has been vaccinated can get a booster shot in the fall. “We could give people a booster shot with the Pfizer vaccine.”
In Korea, cross-vaccination will be carried out from the 5th of next month. Due to the shortage of AstraZeneca vaccine, the government plans to provide a second dose of Pfizer vaccine to 760,000 people who received the first dose of AstraZeneca vaccine.
Ali Elevedi Me., an associate professor at Washington University in St. Louis (right) discusses the research contents. Provided by University of Washington Medical School, St. Louis