Two doses of the Pfizer COVID-19 vaccine are 90 percent effective against hospitalizations from the disease for at least six months for all variants, including Delta, according to a study published Tuesday in The Lancet journal.
The researchers found that during the study period, the vaccine’s effectiveness against all S-CoV-2 infections declined, falling from 88 percent within one month to 47 percent after six months of receiving two vaccine doses.
However, the effectiveness of the Pfizer (BNT162B2) vaccine against hospitalization remained at 90 percent overall for all variants, he said.
Researchers said the study underscores the importance of improving COVID-19 vaccination rates around the world and monitoring vaccine effectiveness to determine which populations should be prioritized to receive booster shots.
“Our study confirms that vaccines are an important tool for controlling epidemics and are highly effective in preventing serious illness and hospitalizations involving delta and other forms of anxiety,” said study lead Said author, Sarah Tartoff from Kaiser Permanente in America. .
“The protection against infection decreases in the months following the second dose,” said Sarah Tartoff.
The researchers noted that booster shots should take into account the global COVID-19 vaccine supply because people in many countries around the world have not yet received their primary vaccination series.
The research team analyzed 3,436,957 electronic health records from the Kaiser Permanente Southern California (KPSC) health system between December 4, 2020 and August 8, 2021, to protect against S-CoV-2 infection and COVID-19-related hospitalizations. To assess the effectiveness of the vaccine.
During the study period, 5.4 percent of people were infected with S-CoV-2. Of those infected, 6.6 percent were hospitalized.
The median time since full vaccination was between three and four months.
The study found that the vaccine’s effectiveness against delta-type infections was 93 percent one month after two doses of Pfizer and dropped to 53 percent after four months.
After taking two doses the effectiveness against other types was 97 percent at one month and decreased to 67 percent after four months, the researchers said.
They said the effectiveness of Delta-related hospitalizations remained high (93 percent) for the duration of the study period.
The researchers did not see any difference in the decreases in incidence between the types of CoV-2 strains.
However, they noted that because Delta became the dominant strain in the middle of the study period, longer follow-up analysis is needed to measure the rate of decline for the variant compared to other strains.
“Our variant-specific analysis clearly shows that the BNT162B2 vaccine is effective against all current forms of anxiety, including delta,” said Luis Jodar, senior vice president and chief medical officer for Pfizer Vaccines.
“People who have received two doses of the vaccine are most likely to have COVID-19 infection, not because of delta or other variants that evade vaccine protection,” Luis Jodar said.
The authors acknowledge some limitations in their study.
The researchers could not determine a causal relationship between vaccination and COVID-19 outcomes because vaccination status was not randomized among the study populations.
They also did not have data on adherence to mask guidelines, social contact, occupation and disease rates in the study population, which may affect the likelihood of contracting and testing for S-CoV-2 infection.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)