Pfizer vaccine prevents severe Covid-19 for at least six months / Article

Two doses of Pfizer vaccine are very effective against severe disease with Covid-19, including the delta variant, for at least six months, found in an analysis of patients in the United States (USA).

Previous data from clinical trials had shown that vaccines protect against hospitalization, but a new study published in the medical journal Lancet measured the effectiveness of the vaccine over time in the real world.

Pharmaceutical company Pfizer and healthcare provider Kaiser Permanente studied data from 3.4 million people in southern California, about a third of whom were fully vaccinated between December 2020 and August 2021.

After an average period of three to four months, 73% of vaccinated people were found to be protected from infection and 90% protected from hospitalization.

Protection against delta infection decreased by 40% over five months, but protection against hospitalization for all Covid-19 variants remained very high throughout the study.

The study notes that these results are in line with preliminary data from the US and Israeli health authorities.

“Our findings emphasize the importance of monitoring vaccine efficacy over time and suggest that booster doses are likely to be needed to restore the initially high levels of protection observed at the beginning of the vaccination program,” the study said.

An additional dose of Covid-19 was approved in the US in August for people with a weakened immune system, while in France an additional dose was offered for the elderly.

Israel has gone even further by offering children aged 12 and over a third dose five months after receiving the second dose.

However, a report published by the World Health Organization (WHO) in September found that current vaccines were effective enough against severe Covid-19 to prevent a third dose from being needed in the general population.

In September, the WHO called for a moratorium on primary vaccination doses by the end of the year in order to overcome inequalities in the distribution of Covid-19 vaccine doses between rich and poor countries.

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