Curing Covid: Russian vaccine Sputnik V safe, produces antibodies

Russia’s Covid-19 vaccine candidate, nicknamed Sputnik V, has proved to be immunogenic — generating an immune system response — against SARS CoV-2 and without any serious adverse effects in early-stage trials.

Findings of non-randomised, phase 1/2 trials of the vaccine have been published by the Russian researchers in The Lancet; this can be held to mean that the research has passed expert scrutiny. This is important because Russia’s Gamaleya Institute’s announcement of the vaccine had been met with widespread scepticism from the global scientific community, especially given it was approved by the Russian government even before early trial data had been shared and phase 3 trial had been approved.

The trial involved 76 healthy participants, aged 18-60, with the vaccine having two adenoviral vector components, both engineered to express the SARS CoV-2’s spike protein. The vaccine was well-tolerated in the subjects in both phases, with the most notable adverse effects being pain at the injection site, fever, headache, weakness and muscular and joint pain. While all participants produced antibodies to SARS CoV-2 spike protein, all 40 participants (of the total of 76) who were part of the phase 2 trial developed cellular immunity (T-cell immunity) and neutralising antibodies.

The vaccine was administered in two forms — frozen and freeze-dried — and the frozen form showed greater efficacy in terms of production of neutralising antibodies and T-cells. This aspect of the research is important, since the freeze-dried form proving effective (even though lesser so than the frozen form) means that the vaccine can be transferred in a stable manner through the existing vaccine cold-chain conditions that maintain the efficacy of a vaccine, eliminating the need for a specialised storage and transfer system. Most vaccine candidates so far have not demonstrated this even if they can be transferred and stored similarly.

The vaccine’s results have been compared with convalescent plasma to understand the immunogenic impact of the vaccine against naturally developed immunity, and it was found that the vaccine induced a stronger immune response.

Experts, as per various media reports, have pointed to the fact that it was a non-randomised trial, with the subjects including a significant number of soldiers (assumed to be fitter and healthier) and many being their 20s-30s. A phase 3 trial involving 40,000 people was approved towards the end of last month.