According to a recent research done in India and published in the journal The Lancet Regional Health Southeast Asia, a booster dosage of Covishield provides the greatest immunological response, regardless of whether the main doses were of Covishield or Covaxin.
The study found that, regardless of whether the primary vaccination series used Covishield or Covaxin, homologous and heterologous boosting with Covishield or Covaxin in Covishield or Covaxin primed individuals are immunogenic and safe. However, boosting with Covishield produced better binding and functional antibodies.
The World Health Organization (WHO) has advised the administration of booster doses after research revealed that the effectiveness of the first SARS-CoV-2 immunization dwindles with time and offers less protection against sickness with new virus variations.
According to the study, which was carried out by scientists from Christian Medical College in Vellore, Tamil Nadu, and the Centre for Cellular and Molecular Biology in Hyderabad, Andhra Pradesh, homologous or heterologous boosters with ChAdOx1 nCoV-19 (Covishield) or BBV152 (Covaxin), the two vaccines that are frequently used for primary immunization in India, were determined to be safe and immunogenic for participants who had already received two primary
The two vaccinations that the majority of Indians take are Covishield and Covaxin. The primary immunization with Covishield followed by a homologous booster or a heterologous Covaxin booster and primary immunization with Covaxin followed by a homologous booster or a heterologous Covishield booster are the four permutations for a booster dose evaluated in this study, according to the research.
Participants were randomly assigned to receive either Covishield or Covaxin booster in a 1:1 ratio after receiving two doses of Covishield or Covaxin each 12 to 36 weeks earlier, according to the research.
Day 28 post-booster anti-spike IgG seropositivity was the main finding, while additional findings included anti-spike IgG levels and evaluations of safety and reactogenicity. The research reported the findings of a 90-day intention-to-treat analysis.
According to the research, in the Covishield primed group of 200 subjects, the heterologous Covaxin arm's seropositivity at 28 days after booster was 99% and non-inferior to the homologous Covishield arm's seropositivity of 99%.
According to the research, the geometric mean concentration (GMC) of anti-spike antibodies on day 28 after receiving a heterologous Covaxin boost was 36,190.78 AU/mL, whereas the GMC after receiving a homologous Covishield boost was 97,445.09 AU/mL.
The seropositivity 28 days after booster in the heterologous Covishield arm in the 204-participant Covaxin primed group was 100% and not inferior to the homologous Covaxin arm's 96%, according to the research.
According to the research, the GMC after a heterologous Covishield boost was 241,681.6 AU/mL as opposed to 48,473.94 AU/mL after a homologous Covaxin boost.
According to the research, the geometric mean ratio (GMR) at day 28 between the heterologous and homologous boosted arms of the anti-spike IgG was 0.42 in the Covishield primed group and 5.11 in the Covaxin primed group. No group reported any connected significant adverse events.
According to research findings, immunogenic and secure homologous and heterologous boosting with Covishield or Covaxin in Covishield or Covaxin primed people. According to the research, among the four tested combinations, a heterologous boost with Covishield after Covaxin prime provided the greatest immune response.
For both binding and functional antibodies, homologous boosting with Covishield is superior than heterologous boosting with Covaxin in people primed with Covishield, while heterologous boosting with Covishield is superior in persons primed with Covaxin.
Among the strategies examined in this research, a heterologous boost with Covishield after a Covaxin main regimen provides the greatest immune response.