Pharmaceutical company Johnson & Johnson said on Wednesday that a second dose of its Covid-19 vaccine boosted immunity conferred by the first, and so far only, injection.

In two clinical trials, the results of which have not yet been submitted to the scientific community, the extra dose generated antibody levels nine times higher than those seen four weeks after a first dose, J&J said in a report. communicated.

The US administration announced last week that a booster campaign for messenger RNA vaccines (Pfizer and Moderna) would start from the end of September.

The health authorities then stressed that a recall would be "probably necessary" for people who received the remedy from J & J, a minority in the United States, but that data was expected "in the coming weeks".

JUST IN: Interim Phase 1 / 2a data suggest booster dose of our # COVID19 vaccine generates rapid, robust increase in spike-binding antibodies in adults (n = 17).

The Janssen COVID-19 Vaccine has not been approved / licensed by FDA.

- Johnson & Johnson (@JNJNews) August 25, 2021

Pfizer and Moderna vaccines 66% effective against the Delta variant

The announcements come as the Centers for Disease Prevention (CDC), the main federal health agency, have indicated that the effectiveness of anti-Covid vaccines has declined with the spread of the Delta variant, which now accounts for the vast majority of contaminations in the United States.

An ongoing study of thousands of healthcare center and hospital workers in six states in the United States showed that the effectiveness of Pfizer and Moderna vaccines in preventing infection increased from 91% to 66% in the face of Delta.

The protection of vaccines against severe cases of illness, hospitalizations and death, however, remains high, exceeding 90% according to most studies.


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  • Anti-covid vaccine

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