After the initial vaccination series, studies have demonstrated that a booster dose of the COVID-19 vaccine can improve protection.
A booster dose is an extra dose administered after completing the "primary vaccination series." WHO explains that the objective is to "restore vaccine effectiveness from that deemed no longer sufficient." An additional dose is administered as an extended dose in the primary series for a targeted population. WHO explains that the objective "is to optimize or enhance the immune response to establish a sufficient level of effectiveness against disease."
An article by Nature highlighted that the new studies have shown "immunological benefits of COVID-19 vaccine boosters." The report explained that the primary vaccination doses establish a rapid immunity in an individual's body, however with time, it wanes and leads to diminishing effects. The booster shots help to restore the effect and provide a long duration of safety from the infection. The above conclusions were made from the studies on the safety and immunogenicity of COVID-19 booster shots. It should be considered that "Vaccine immunogenicity and effectiveness at an individual level varies according to multiple factors, including age and immune competency," added the report.
Katherine O'Brien, epidemiologist, and vaccinologist spoke at WHO's Science in 5 on booster shots. Katherine pointed out that ''the evidence right now shows that the vaccines are holding up extremely well to protect you against severe disease, hospitalization or even death." Further, she agreed that the evidence showing the third dose led to an increase in immune response was true.
Centers for Disease Control and Prevention(CDC) states that the studies have proven vaccines' positive response towards the Delta variants. Hence for continuous protection from variants, booster doses are necessary. Even the CDC listed that clinical trials' data reflected that "booster shot increased the immune response in trial participants."
WHO states that "with support of the Strategic Advisory Group of Experts (SAGE) on Immunization and its COVID-19 Vaccines Working Group, continues to review the emerging evidence on the need for and timing of a booster dose for the currently available COVID-19 vaccines which have received Emergency Use Listing (EUL)."
In all trials, booster doses increased immune response or built immunity in those with poor immunological development. As a result, the claim that a COVID-19 booster shot impairs a previously vaccinated person's immune system is false.
The COVID-19 pandemic has given rise to a lot of potentially dangerous misinformation. For reliable advice on COVID-19, including symptoms, prevention, and available treatment, please refer to the World Health Organization or your national healthcare authority.