The latest results on the peer-reviewed general medical journal, The Lancet suggest that Phase-1 and Phase-2 clinical trials of Russia’s first registered COVID-19 vaccine, Sputnik V, has triggered antibody response with no serious side effects in human trials.
Sputnik V was approved by the Russian government on August 11 without conducting any Phase-3 trials, which led to widespread global criticism.
Results from initial non-randomized vaccine trials in a total of 76 people showed a better safety profile of more than 42 days for both formulations of the vaccine. The trials also confirmed that the vaccine evokes antibody responses in all participants within 21 days.
The researchers said that the secondary results from the trial indicate that the vaccine produced a T-cell response within 28 days.
The findings are based on two small phase trials lasting 42 days, one studying a frozen formulation of the vaccine, and another involving a lyophilized (freeze-dried) formulation of the vaccine.
The frozen formulation is concentrated for large-scale use in current global vaccine supply chains, while the freeze-dried formulation has been produced for the region which is hard to reach because it is more durable and can be stored at 2-8 degrees Celsius.
Developed by Moscow’s Gamaleya Institute, the vaccine uses two adenoviruses to inject the genetic material of the novel coronavirus into humans in order to activate an immune response.
Adenoviruses, which cause a range of respiratory diseases in human beings, are used as carriers to deliver several existing drugs and vaccines for other diseases as well, after eliminating their ability to replicate.
The vaccine developers conducted two independent trials at two hospitals in Moscow, both involving Phase-1 and Phase-2 and they were a total of 76 participants in which both place contains 38 each.
Using different adenoviruses, two variants of the vaccines were used in the trials. In the first phase of each study, nine participants were injected with one formulation and the other nine were injected with another formulation. In the second phase of both studies, 20 participants were given shots of both formulations.
“To form a powerful immune response against SARS-CoV-2, it is important that a booster vaccination is provided. However, booster vaccinations that use the same adenovirus vector might not produce an effective response because the immune system may recognize and attack the vector (carrier). This would block the vaccine from entering people’s cells and teaching the body to recognize and attack SARS-Cov2. For our vaccine, we use two different adenovirus vectors in a bid to avoid the immune system from becoming immune to the vector,” said lead author Denis Logunov of Gamaleya Institute on the usage of two formulations in the experiment.
The Lancet results
The Lancet published that both vaccine formulations are safe. But some participated did complaints on small side effects which are not serious. 58 percent of the participants told about the difficulty during the injection time which was the common problem complained by the participants. And other problems that were found are hyperthermia or high temperature in 50 percent, headache in 42 percent, asthenia or lack of energy in 28 percent and muscle and joint pain in 24 percent participants. Most adverse events were mild and no serious adverse events were detected during the trial period.
Significance of findings
The results show that the vaccine is safe to use and does not harm the individual. However, the relatively small number of volunteers who participated and the short duration of follow-up (42 days) did not satisfy all experts.
The absence of the Phase 3 trial raises lots of questions on the effectiveness of the vaccine. In the third phase, a vaccine candidate is tested on hundreds of volunteers in real-life situations outside of laboratory conditions, to assess whether the immune response generated can effectively combat the disease. Participants are usually followed for months to learn about the impact of the vaccine on their ability to prevent disease.
Following the criticism, Russia said that Phase 3 will conduct as well and that the August 11
the authorisation was only “conditional”. Phase 3 trials are planned to begin soon in several countries. The developers had earlier planned to test the vaccine for 2,000 volunteers in the third phase but later announced that 40,000 people would be enrolled in the trial.