COVID-19 infection risk rises 90 days after second vaccine dose: UK Study

0
13

The findings confirm that the Pfizer-BioNTech vaccine provided excellent protection in the early weeks after vaccination, but suggest that protection diminishes for some individuals over time.

London: All countries have started vaccinating their people against COVID-19, reducing the risk of the deadly virus. The pandemic is still ongoing and people are being told that two doses will make them less vulnerable to the virus and also the severity will not be as intense as if not vaccinated. Now, a new study finds a gradual increase in the risk of COVID-19 infection 90 days after receiving a second dose of the Pfizer-BioNTech vaccine.

The results confirm that protection decreases over time and suggest that a third (booster) dose may be needed. The findings of the study were published in the journal ‘BMJ’.

The study was carried out by the Research Institute of Leumit Health Services in Israel. Israel was one of the first countries to launch a massive COVID-19 vaccination campaign in December 2020, but it has seen a resurgence of infections since June 2021.

The findings confirm that the Pfizer-BioNTech vaccine provided excellent protection in the early weeks after vaccination, but suggest that protection diminishes for some individuals over time.

Across the world, large-scale COVID-19 vaccination campaigns are helping to control the spread of the virus, but even in countries with high vaccination rates, breakthrough infections can occur, which scientists think may increase immunity over time. due to gradual loss.

Examining the time since vaccination and the risk of infection can provide important clues about the need for a third injection and its preferred timing.

To do this, the researchers examined electronic health records for 80,057 adults (mean age 44 years) who received a PCR test at least three weeks after their second injection and had no evidence of previous COVID-19 infection. .

Of these 80,057 participants, 7,973 (9.6 per cent) had a positive test result. These individuals were then matched to negative controls from the same age and ethnic group who were tested the same week.

The rate of positive results increased with the passage of time after the second dose. For example, across all age groups, 1.3 percent of participants tested positive 21–89 days after the second dose, but this increased to 2.4 percent after 90–119 days; 4.6 percent after 120-149 days; 10.3 percent after 150-179 days; and 15.5 percent after 180 days or more.

And taking into account other potentially influencing factors, the researchers found a significantly increased risk of infection with the passage of time after the second dose.

The risk of infection was 2.37-fold higher after 90-119 days in all age groups, compared to the initial 90 days after the second dose; 2.66 times higher after 120-149 days; 2.82 times higher after 150-179 days; and 2.82 times more after 180 days or more.

The researchers acknowledge that the interpretation of their findings is limited by observational design, and they cannot rule out the possibility that other uncontrolled factors such as household size, population density, or virus strain may have an effect.

However, this was a large study of people who all received the same vaccine, and the researchers were able to conduct a detailed analysis of the data, suggesting that the results are strong.

As such, they concluded that individuals who received two doses of the Pfizer-BioNTech vaccine showed reduced protection over time, and that the risk of breakthrough infection increased progressively compared to the protection provided during the initial 90 days. .

He said the results suggest that a third dose of the vaccine may be considered. (ANI)

First Published:November 26, 2021, 6 am

Leave a Reply