- The author of this article is Dr Gajendra Singh, Public Health Expert
Pandemic has brought forth not only the shortcomings, struggles, hardships but also the strength and hard work of researchers around rapid development of vaccines across the world. The medical fraternity dedicatedly focused their energies on extensive trials to bring to you, a vaccine that hopes to give immunity against coronavirus.
One such vaccine that recently completed a year since it got registered is Sputnik V. Sputnik V has been approved in 69 countries with total population exceeding 3.7 billion people.
How much do we know about this vaccine and its inception?
Russia started clinical trials of a COVID-19 vaccine in June 2020. On August 11, Sputnik V vaccine was registered by the Ministry of Health of Russia and became the world’s first registered vaccine against Covid-19 based on the well-studied human adenoviral vector-based platform.
To ensure lasting immunity Russian scientists came up with a breakthrough idea to use two different types of adenovirus vectors (rAd26 and rAd5) for the first and second vaccination, boosting the effect of the vaccine. Sputnik V is a two-vector vaccine against coronavirus. Scientists have made use of human adenoviruses as vectors because these viruses, which cause the common cold, are not novel and have been around for thousands of years.
Backed by renowned studies
Earlier this year, the Lancet, one of the most reputed journals in the world, published the outcomes of the phase III of the clinical trials of Sputnik V. The trial results showed a consistent strong protective effect across all participant age groups. Also known as Gam-COVID-Vac, the vaccine uses a heterologous recombinant adenovirus approach using adenovirus 26 (Ad26) and adenovirus 5 (Ad5) as vectors for the expression of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein. The use of two varying serotypes, which are given 21 days apart, is intended to overcome any pre-existing adenovirus immunity in the population. Among the major COVID vaccines in development to date, only Gam-COVID-Vac uses this approach.
Since the 1980s, the Gamaleya Center led the effort to develop a technological platform using adenoviruses, found in human adenoids and normally transmitting the common cold. The Gamaleya Center successfully developed and registered in 2015 two vector-based vaccines against Ebola fever using the adenovirus vector platform. The have vaccines been officially approved for use by the Russian Health Ministry. About 2,000 people in Guinea received injections of Gamaleya vaccines in 2017-18.
How effective has it proven against the virus and its variants?
Sputnik V has also pioneered the unique heterogeneous boosting (“vaccine cocktail”) approach based on use of two different human adenoviral vectors for two injections in the course of vaccination to achieve stronger and more durable immunity.
Vaccination with Sputnik V has produced protective neutralizing titers against new variants, including Alpha B.1.1.7 (first identified in UK), Beta B.1.351 (first identified in South Africa), Gamma P.1 (first identified in Brazil), Delta B.1.617.2 and B.1.617.3 (first identified in India) and Moscow endemic variants B.1.1.141 and B.1.1.317 with mutations in the receptor-binding domain (RBD).
According to Russian Ministry of Health, Sputnik V is 83.1% effective against the Delta variant and shows 6x reduction of infection risk. Sputnik V is also 94.4% effective against hospitalisations with 18x reduction in hospitalization risk.
Prior to a vaccine being introduced into a country’s vaccine system, there needs to be investigation with respect to the efficacy, safety, immunogenicity, and manufacturing for regulatory and public health policy approvals. Supported by renowned scientific study, Sputnik V holds its ground on all the above-mentioned prerequisites for an efficient vaccine. Governments should work to broaden the basket of choice to ensure vaccination to all eligible population.
