Last month Russian President Vladamir Putin surprised the scientific community by announcing that the Russian authorities had approved the world's first COVID-19 vaccine – Gam-COVID-19. This was in spite of that fact that no scientific data published about its safety or efficacy and no large-scale trials of the vaccine had been completed.
Today, the much-awaited safety and immunogenicity data of two early Phase clinical trials of Gam-COVID-19 have been published in the medical journal The Lancet, and experts have been quick to provide their thoughts on the data.1 Developed by Moscow's Gamaleya Institute, Gam-COVID-19 is an adenovirus-based vaccine, like the ChAdOx1 vaccine developed by the University of Oxford that is currently in Phase I/II and Phase III trials.
The trials of Gam-COVID-19 (NCT04436471 and NCT04437875), conducted in June of this year, recruited a sample cohort of 76 healthy individuals ages 18-60 years. Both were non-randomized 42-day trials.
The trial results published in The Lancet state that the vaccine was well tolerated, producing humoral and cellular immune responses in the sample cohort. 100 percent of the sample cohort developed antibody responses to SARS-CoV-2, and presented with mean antibody titres that measured significantly higher than samples obtained from recovered COVID-19 patients.
The general response of the scientific community is that the results are encouraging, although concerns have been raised about the size of the trials.
Brendan Wren, professor of microbial pathogenesis at the London School of Hygiene and Tropical Medicine said: “The data on the Russian vaccine studies reported in The Lancet are encouraging – demonstrating the safety and immunogenicity of the adenovirus-based COVID-19 vaccines." He added that these results are "unsurprising" considering the Oxford research group have also demonstrated that adenovirus-based vaccines do not produce major side effects in humans.
"The study is undertaken to a good standard on 76 subjects up to 60 years of age," Wren said. This is a critical aspect of the trial design, as clinical outcomes of infection with COVID-19 are typically worse in the very elderly population. The Phase I/II trials do not test the safety and efficacy of the vaccine on this specific age group where the vaccine is perhaps most required.
Dr Ohid Yaqub, senior lecturer at the SPRU (Science Policy Research Unit), University of Sussex, said that another potential flaw in the design of the trials is the lack of randomization. “Normally, such a study would be the basis for debating whether to proceed into larger trials and the costs that entails. In that context, the study results are encouraging in terms of safety and possible efficacy," he said.
But previous statements made by the Russian authorities about the next steps for Gam-COVID-19 are somewhat ambiguous. "In the context of regulatory approval, the design and size of a Phase I/II study is not anywhere near sufficient for widely recognised standards of approval. The study was not randomized, and it was not large enough to detect rarer safety issues," Yaqub commented.
His thoughts are echoed by Michael Head, senior research fellow in global health at the University of Southampton. Head wants transparency in the context of COVID-19 vaccine development across the globe and believes that this is important when considering the potential impact of vaccine hesitancy.
He said: "At this stage, we do not know if the vaccine actually works – that is what the Phase III trials will tell us. Public confidence in any licensed vaccine is vital, and suggestions from both Russia and the USA that a vaccine may be fast-tracked without the proper research having taken place are problematic. We must be open and transparent about the effectiveness and safety profiles of all vaccine candidates. Ultimately, we must not pour additional fuel on the anti-vaccine lobby fires.”
Professor Eleanor Riley from the University of Edinburgh emphasizes that the big question is: What will happen next? "The key question is whether the next step for this vaccine is indeed (as we would expect) a randomized, blinded, placebo controlled Phase III trial or whether the vaccine developers will come under political pressure to release doses of vaccine for administration to the general public. The approval granted for the vaccine – apparently under a law introduced after the onset of the pandemic – allows for both," she said.
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1. Logunov DY, Dolzhikova IV, Zubkova OV, et al. Safety and immunogenicity of an rAd26 and rAd5 vector-based heterologous prime-boost COVID-19 vaccine in two formulations: two open, non-randomised phase 1/2 studies from Russia. The Lancet. doi:10.1016/S0140-6736(20)31866-3.