One Shot of the Sputnik V COVID-19 Vaccine Triggers Strong Antibody Responses

A single dose of the Sputnik V vaccine can elicit significant antibody responses against SARS-CoV-2, finds a study published July 13, 2021 in the journal Cell Reports Medicine.

“Due to the limited supply of vaccines and the uneven distribution of vaccines in many regions of the world, health authorities urgently need data on the immune response to vaccines to optimize vaccination strategies,” said senior author Andrea Gamarnik (@GamarnikLab) of the Fundación Instituto Leloir -CONICET in Buenos Aires, Argentina. “The peer-reviewed data we present provide information to guide public health decisions in the face of the current global health emergency.”

Previous research has shown that two doses of Sputnik V result in 92% efficacy against the 2019 coronavirus disease (COVID-19), which is caused by SARS-CoV-2. An important question is whether a single dose provides more health benefits than two doses by protecting a larger population more quickly.

Evidence from other vaccines supports the one-shot approach. The AstraZeneca vaccine shows efficacy of 76% after a single dose, and the Moderna and Pfizer vaccines can elicit sufficient immunity after a single dose in previously infected individuals, with no apparent benefit from an additional dose.

This graphic summary shows antibody responses to the Sputnik V vaccine in Argentina. Top schematic representation of the two component adenovirus-based vaccine (rAD26 and rAD5) Sputnik V. Bottom, IgG antibody levels measured by international units and SARS CoV-2 neutralizing titers in vaccinated naive (seronegative, blue) and previously infected (seropositive, red) volunteers. There is a high seroconversion rate after the first dose in naive subjects. In previously infected participants, a single dose of Sputnik V elicits a rapid and robust antibody response with no apparent benefit from a second dose. Credit: Rossi and Ojeda et al./Cell Reports Medicine

In the Cell Reports Medicine study, Gamarnik and her colleagues compared the effects of one and two shots of Sputnik V on SARS-CoV-2 specific antibody responses in 289 health professionals in Argentina. Three weeks after the second dose, all volunteers with no previous infection generated virus-specific immunoglobulin G (IgG) antibodies – the most abundant type of antibody found in blood.

But even within three weeks of receiving the first dose, 94% of these participants developed IgG antibodies to the virus, and 90% showed signs of neutralizing antibodies, which interfere with viruses’ ability to infect cells.

Additional results showed that IgG and neutralizing antibody levels in previously infected participants were significantly higher after one dose than those in fully vaccinated volunteers with no history of infection. A second dose did not increase neutralizing antibody production in previously infected volunteers.

“This highlights the potent response to vaccination of previously infected individuals, suggesting that naturally acquired immunity can be sufficiently enhanced by a single dose, consistent with recent studies of mRNA vaccines,” says Gamarnik.

Further studies are needed to evaluate the duration of the immune response and to assess how antibody levels relate to vaccine protection against COVID-19. “Evidence based on quantitative information will guide vaccine deployment strategies in the face of global vaccine delivery constraints,” said Gamarnik.

Reference: “Sputnik V Vaccine Triggers Seroconversion and Neutralizing Potential to SARS CoV-2 After a Single Dose” by Andres H. Rossi, Ph.D.; Diego S. Ojeda, Ph.D.; Augusto Varese, Ph.D.; Lautaro Sanchez, M.Sc.; Maria M. Gonzalez Lopez Ledesma, Ph.D.; Ignacio Mazzitelli, MD; Anabel Alvarez Julia, Ph.D.; Santiago Oviedo Rouco, Ph.D.; Horacio M. Pallares, M.Sc.; Guadalupe S. Costa Navarro, M.Sc.; Natali Rasetto, M.Sc.; Corina I. Garcia, Ph.D.; Shirley D. Wenker, Ph.D.; Lila Y. Ramis, MD; Magali G. Bialer, Ph.D.; Maria Jose de Leone, Ph.D.; C. Esteban Hernando, Ph.D.; Santiago Sosa, M.Sc.; Luciana Bianchimano, M.Sc.; Antonella Rios, M.Sc.; Maria Soledad Treffinger Cienfuegos, M.Sc.; Julio J. Caramelo, Ph.D.; Yesica Longueira, M.Sc.; Natalia Laufer, Ph.D.; Diego Alvarez, Ph.D.; Jorge Carradori, MD; Dariana Pedrozza, MD; Alejandra Rima, MD; Cecilia Echegoyen, MD; Regina Ercole, MD; Paula Gelpi, MD; Susana Marchetti, MD; Martin Zubieta, MD; Guillermo Docena, Ph.D.; Nicolas Kreplak, MD; Marcelo Yanovsky, Ph.D. and Jorge Geffne, July 13, 2021, Cell Reports Medicine.
DOI: 10.116/j.xcrm.2021.100359

This work was supported by the National Institutes of Health (NIAID) and by Argentina’s National Ministry of Scientific Technology and Innovation.