A booster dose of Covishield provides the best immune response, regardless of whether the primary dose was of Covishield or Covaxin, according to a new study India and is published in the Lancet Regional Health Southeast Asia Journal.
According to the study, although homologous and heterologous boosting with Covishield or Covaxin are immunogenic and safe in Covishield or Covaxin primed individuals, boosting with Covishield produced better binding and functional antibodies, regardless of whether Covishield or Covaxin was used in the primary immunization series. have been used.
Primary SARS-CoV-2 vaccination has been shown to wane over time and provide less protection against disease with newer viral variants, leading to World Health Organization (WHO) to recommend the administration of a booster dose.
Study by researchers from Christian Medical College, Vellore, Tamil Nadu and Center for Cellular and Molecular Biology, Hyderabad, Andhra Pradesh determined the safety and immunogenicity of homo or heterologous boosters with ChAdOx1 nCoV-19 (Covishield) or BBV152 (Covishield) Has been done. Covaxin), the two vaccines widely used for primary immunization in India, in participants who had already received two primary doses of these vaccines.
Covishield and Covaxin are two such vaccines that are used by most of the Indian population. The four permutations for booster doses evaluated in this study are 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 booster, the study said. Heterogeneous Covishield boosters, says the study.
Participants who took two doses of either Covishield or Covaxin 12-36 weeks earlier were randomized in a 1:1 ratio to receive either Covishield or Covaxin boosters, the study said.
The primary outcomes were day 28 post-booster anti-spike IgG seropositivity and the secondary outcomes were anti-spike IgG levels and assessment of safety and reactivity. The study presented the results of a 90-day intent-to-treat analysis.
The study noted that in the Covishield primed group with 200 participants, the heterologous Covaxin arm had 99 per cent seropositivity after 28 days of booster and was no less than the homologous Covishield arm, which was also 99 per cent.
The geometric mean concentration (GMC) of anti-spike antibodies after the heterologous Covaxin boost on day 28 was 36,190.78 AU/mL, while the GMC after the homologous Covishield boost was 97,445.09 AU/mL, the study said.
The study noted that in the Covaxin primed group with 204 participants, the heterologous Covaxin arm had 100 percent post booster seropositivity at 28 days and was no less than the homologous Covaxin arm, which was 96 percent.
The study noted that the GMC after the heterologous Covishield boost was 241,681.6 AU/mL, while the homologous Covaxin boost was 48,473.94 AU/mL.
The study noted that the 28-day geometric mean ratio (GMR) of anti-spike IgG between the heterologous and homologous boosted arms was 0.42 in the Covishield primed group and 5.11 in the Covaxin primed group.
There were no related serious adverse events reported in either group, the study noted.
Based on study results, homologous and heterologous boosting with Covishield or Covaxin in Covishield or Covaxin-primed individuals are immunogenic and safe.
The study found that a heterologous boost with Covishield followed by Covaxin prime provided the best immune response out of the four combinations evaluated.
For both binding and functional antibodies, in participants primed with Covishield, homologous boosting with Covishield provided a better immune response than heterologous boosting with Covaxin; And in primary with Covaxin, heterologous boost with Covishield provides better immune response.
A heterologous boost with Covishield following the Covaxin primary schedule provided the best immune response among the approaches evaluated in this study.
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