BOOSTER shots can increase by ten-fold the number of antibodies in someone's body to fight covid19 infection, the China Sinopharm International Corporation said in a statement on Monday, following a local media story on Sunday questioning the vaccine's general efficacy.
Sinopharm said, "Based on the current research progress, many countries have started inoculating booster shots to maintain and improve the protective efficacy of covid19 vaccines.
"The results of Sinopharm covid19 vaccine phase three clinical study for booster immunisation exhibited good safety and immunogenicity after the third dose."
Immunogencity means a vaccine's ability to provoke an immune response in the body.
A booster given at six, eight or 12 months after the second dose had significantly enhanced people's antibody levels, the statement said.
"The strongest growth appeared at the interval of six months," said Sinopharm, "the neutralising antibody increasing ten times comparing with that after the second dose."
Experiments proved the third dose induced a "considerable protective effect" against delta variant, the statement said.
Sinopharm said local adverse reactions after the third dose were not significantly different from those after the first two doses and the incidence of systemic adverse reactions was lower than after the first two doses. The CDC website said local reactions included redness, while systemic reactions included fever.
The statement said a study, Robust induction of B cell and T cell responses by a third dose of inactivated SARS-CoV-2 vaccine, said the Sinopharm vaccine generated long-term immunological memory. (B cells and T cells are types of white blood cell of the lymphocyte subtype in the body's immune system.)
"The immune memory of healthcare workers with low serological response to two doses was also quickly recalled by a third dose of Sinopharm covid19 vaccine."
Another study, Potent antibody immunity to SARS-CoV-2 variants elicited by a third dose of inactivated vaccine, found that a third dose of Sinopharm worked well against the beta, delta, and lambda variants. The statement also suggested a third dose gave "a more potent and longer protection."
Sinopharm said its vaccine has been approved as a booster in China, UAE, Bahrain, Barbados, Mauritius, Mongolia and Namibia.
"Tens of millions of people have received the Sinopharm booster dose.
"The pandemic situation is still severe. As China's major anti-epidemic force, Sinopharm is willing to continuously contribute to the global anti-epidemic fight and will stand with governments of all countries to build a protective shield to safeguard people's lives and health."
The statement justified boosters for all types/platforms of covid19 vaccines in use worldwide.
"After large-scale use, data from real-world research shows that it is unavoidable that antibody levels will decline after complete vaccination, regardless of the platforms, which will weaken the protective efficacy of vaccines.
"Based on the current research progress, many c
