Sinopharm vaccine studies have shown that heterologous enhancement of immune safety has significantly improved the neutralization efficacy of Omiclon

According to a large-scale clinically controlled study of vaccines published this week by Yang Xiaoming, chairman of Sinopharm China Biologics, and researchers at Sheikh Khalifa Medical City in Abu Dhabi, a recombinant protein vaccine produced by Sinopharm can significantly improve the efficacy of COVID-19 immune protection against covid-19, including the Ami kerong variant.

This is the first large-scale randomized controlled trial of heterologous initial immunity-boosted vaccination using inactivated vaccines and recombinant protein subunit vaccines, the researchers write. The results of the trial show that cross-enhanced vaccination of people who have been vaccinated with two doses of Sinopharm inactivated vaccine (BBIBP-CorV) using Sinopharm's new generation of covid-19 protein vaccine (NVSI-06-07) is safe and immunogenic.

Sinopharm's NVSI-06-07 protein vaccine was approved for emergency use as a booster in the UAE last December. The study in the UAE was a single-centered, randomized, double-blind, controlled Phase II trial in which 1,800 volunteers who had received two doses of inactivated SINEF vaccine were enrolled, and 899 of them were treated with heterologous enhancement of the NVSI-06-07 protein vaccine and 901 participants received homologous inactivated vaccination. The study did not report vaccine-related serious adverse events (SAEs) and adverse events of particular concern (AESI).

The results of the study showed no significant difference in overall safety between heterologous and homologous enhancement, but heterologous enhancement significantly improved immunogenicity against the original strain of COVID-19 and variants of COVID-19, including Omilkerong, compared with homologous enhancement. "Since there is currently no specific vaccine available against Themikron, xogenous initial immunity-boosted vaccination can be an effective strategy against the Omiljun strain." The researchers wrote.

The immunogenicity assay showed that on the 28th day after boosting immunity, the serum conversion rate of neutralizing antibodies against the original strain of new crown induced by heterologous enhancement was 89.96% to 97.52%, which was much higher than the seroconversion rate of 36.80% to 81·75% induced by homologous enhancement. Similarly, in the heterologous booster immune group, the neutralized geometric mean titer (GMT) for prototype strains increased by 21.01 to 63.85 times from baseline to 28 days after booster inoculation, while the homologous booster group increased only by 4.20 to 16.78 times. For the Omiljung variant, the level of GMT neutralizing antibody induced by heterologous enhancement was 292.53, which is about 8 times the GMT value of 37.91 induced by homologous enhancement immune.

Similar results were obtained for other variants including Alpha, Beta, and Delta, and the neutralization response caused by heterologous strengthening was significantly greater than that of homologous strengthening, the study said. An earlier study of The National Medicine Vaccine showed that the three-dose inactivated vaccine was less effective at neutralizing the Omiljunn variant than it was in the original strain of COVID-19.

The study highlighted that among subjects who received the second dose of vaccination for more than 6 months, the increased value of GMT was the largest, with an increase of 63.85 times and 16.78 times, respectively, whether heterologous or homologous booster immunization. Therefore, it is recommended that the intensive vaccination strategy with intervals of more than 6 months is optimal. But the researchers also point out that further studies are needed to assess the long-term protective effects of heterologous boosting immunity, and the study is still to be peer-reviewed.

The latest findings are also consistent with those published in the journal EMI by the team of Professor Zhang Wenhong, director of the Department of Infectious Diseases at Huashan Hospital affiliated to Fudan University, in December last year. Zhang Wenhong's team compared the inactivated vaccine (BBIBP-CorV) homologous reinforcement group and the inactivated vaccine-protein subunit vaccine (BBIBP-CorV/ZF2001) heterologous reinforcement group and found that on the basis of the two-shot inactivated vaccine, the homologous and heterologous third dose enhancement increased the human body's neutralization ability to Omiljung by 8.07 times and 15.87 times, respectively, suggesting that heterologous enhancement vaccination can induce high immune response. But the study only tested small samples and did not conduct live virus neutralization tests.