Canada allows use for children from 12 to 15 years old – Photo: REUTERS
American pharmaceutical company Pfizer and its joint venture is German pharmaceutical company BioNTech says their claim is based on two Israeli studies that showed “another booster dose (4th dose) increase immunity and reduce the rate of confirmed infections and severe cases”.
According to AFP news agency, the infection level of most countries has dropped significantly from the record level during the Omicron wave. In many countries, the epidemic is stabilizing or starting to increase as authorities lift restrictions and the protective effects of previous doses of vaccines begin to fade.
The first Israeli study cited by Pfizer-BioNTech showed “2 times lower rates of confirmed infections and 4 times lower rates of severe illness in people who received an additional dose of vaccine (the second dose). 4) compared with those who received only one additional dose (3rd dose).
This study was limited to people 60 years of age and older who received a second booster four months after the first booster.
The second study – conducted with healthcare workers 18 years of age and older in Israel – found that antibody levels were significantly higher in those who received the fourth dose of the vaccine compared with those who received the three doses.
“The study did not reveal new safety concerns in individuals receiving a second dose of the supplement,” said Pfizer-BioNTech.
Because the initial regimen of the Pfizer-BioNTech vaccine is two doses, the second booster is also known as the fourth shot.
Recent studies have shown that while a 3rd dose of mRNA vaccine increased antibody levels higher than those of the original regimen, a 4th dose of vaccine despite increasing neutralizing antibody levels of the vaccinated person but was not significant and did not exceed the level observed immediately after the 3rd dose.
Israel and a number of European countries have approved a second dose of the vaccine for the elderly, immunocompromised people, who are most at risk of severe illness.