A new study by Christian Medical College (CMC) Vellore has suggested that mixing vaccines for COVID-19 shows a mixed result depending on the initial vaccination schedule, presenting programmatic challenges moving forward.
The government, in light of this newfound data, has suggested that they may not allow booster doses of COVID-19 vaccines other than the one used for primary vaccination. This retains current recommendations that do not allow for mixed vaccine boosters, only allowing for the same vaccine to be used throughout any subsequent immunisations.
The study suggests that within the initial immunisations there can actually be a significant benefit to mixing doses – depending on the initial vaccines used. The research group found that administering a booster dose of Covishield after primary vaccination with Covaxin gives six to ten times higher antibody levels compared to when Covaxin is given as a booster dose following an initial vaccination schedule with the same vaccine.
“However, the same advantage was not observed when Covaxin as a booster shot was given after two Covishield doses,” an official source told PTI. “Considering programmatic challenges the matter would now be discussed in the National Technical Advisory Group on Immunisation (NTAGI) Standing Technical Sub-Committee meeting for final recommendation.”
While mixing doses could hold the potential for a much higher antibody count in a subsection of the population, those who have had an initial vaccination schedule that used Covishield would seemingly have an inferior level of protection should mixing doses be allowed. This presents a logistical challenge where multiple vaccines would need to be made available even within a single area to optimise immunity. Given this would need to be applied to a population exceeding a billion people, and into often difficult to reach rural areas, it may be near impossible.
India’s current caseload is very low, especially when compared to many other countries that still struggle with a high burden. 2,841 new cases and nine deaths were reported in the last 24 hours according to the Ministry of Health and Family Welfare. Active cases have come down by 463 cases in this timeframe.
Overall COVID-19 death tolls have been disputed, however, leading to disagreements between the Government and the World Health Organization (WHO). India’s official death toll places the figure at 520,000, however, the WHO has cited studies that suggest the figure could be as high as four million.
While the caseload may be low, there is an ever present possibility that COVID-19 will show a resurgence. The recent outbreaks in China serve to underline this fact. Moving forward, immunisation must be made a priority to avoid yet another outbreak that places a catastrophic toll on the healthcare system.