The relative effectiveness of the fourth dose of a COVID-19 vaccine in the elderly was negligible within months, according to a new study.
Researchers in Italy measured the Relative Vaccine Effectiveness (RVE) against infection and severe disease. In other words, they compared the effectiveness of the fourth vaccine dose with the third dose. The population studied was people 80 years old and older.
Researchers found that the relative effectiveness against infection became negligible after two to four months. The relative effectiveness against severe illness was about 30 percent in the same time interval.
The study was conducted from April 11 to Aug. 6, when Omicron BA.2 and BA.5 subvariants were dominant, and published in Vaccine on Nov. 17….