KOCHI: In the wake of increasing breakthrough infections, the demand for vaccine booster dose is getting stronger. Though mixing and matching of Covid vaccines so far have proven effective with immunological benefits, the chances are high for it to be considered for booster doses.Various studies and researches are progressing in India and globally on the benefits of the new formula.
According to experts, advocating a booster dose is easier said than done. Challenging aspects on deciding the booster dose including its effectiveness with the existing variants and clarity on the response of the T-cells should be analysed. “Breakthrough infection is a fact and, therefore, booster doses are needed. But there are some key factors to be considered regarding boosters. More clarity is required on the breakthrough infections, which may be due to waning antibodies as well as new variants with immune escape capabilities. Since booster doses are considered after six-nine months,which is commonly cited as protective immunity after receiving primary doses, it is necessary to ensure that new variants are also covered by the boosters,” said infectious disease expert Dr Anup R Warrier.
World Health Organisation has advised a halt to Covid vaccine boosters mainly on equity grounds. Due to lack of supply of vaccines, many countries are in need and people are yet to receive the first dose. “Other factors including clarifications on non-antibody-mediated immune duration (T-cell), whether to consider giving boosters to people who have recovered from Covid infection, and unavailability of new-generation vaccines to cover variants like Delta and Lambda should be considered. Lastly, vaccination-related adverse events, though in low numbers, are not negligible from an individual standpoint. Hence, we would also hope for a more safe vaccine when considering additional doses,” said Dr Anup.
Recently, the Drugs Controller General of India has given permission to conduct research on mixing both the vaccines —Covaxin and Covishield. Further studies being conducted in this field will be able to throw more light on the booster doses, say experts. “Though breakthrough infections are high especially among health workers, the number of people getting severely affected is less. Therefore, this would be the ideal time for the government to initiate more studies to know the immunogenicity among those vaccinated,” said Dr G Vijayaraghavan, vice-chairman and founder-director of the Kerala Institute of Medical Sciences.
Challenging task ahead
Challenging aspects on deciding the booster dose including its effectiveness with the existing variants and clarity on the response of the T-cells should be analysed.
Booster doses are considered after six to nine months of the primary doses, which are commonly cited as the duration for protective immunity