Filenews 26 July 2021
Research data as well as data from vaccination of the general population have confirmed the high protection provided by vaccines against serious disease and the risk of death from COVID-19. Indeed, noted Jennifer Juno and Adam Wheatley, senior researchers at the Peter Doherty Institute of Infections and the Department of Microbiology at the University of Melbourne respectively, protection rates range from 50% (Sinovac) to 95% (Pfizer/BioNTech).
However, a big question mark remains how effective SARS-CoV-2 coronavirus vaccines are in transmission of the virus, especially after cases of people infected after full vaccination. The constantly updated scientific data is moving on an optimistic path.
Lower risk of transmission from vaccinated
Although animal studies had early on confirmed that immunisation from COVID-19 vaccines also reduces the risk of transmission, efficacy in humans has only recently been found. In April, Public Health England announced the results of a study that included more than 365,000 households with vaccinated and unvaccinated members.
According to the findings, the Oxford/Astra Zeneca and Pfizer/BioNTech vaccines reduced the chances of transmission of coronavirus by 40-60%.
Another study by vaccination pioneer Israel concluded that in the 5,000 cases of coronavirus in the vaccinated population, the viral load on the nasal smear was significantly lower than that of unvaccinated people diagnosed with the virus. It is recalled that the concentration of the virus in the nasal cavity is directly proportional to the risk of transmission.
What changes and what remains after vaccination
Reduced dispersion thanks to vaccines is becoming an essential weapon in the battle for herd immunity and pandemic control. At the same time, stopping cases and reducing the virus in the community are necessary for groups of the population that have experienced a weak immune response or cannot yet be protected from vaccines such as minors, some elderly and some immunosuppressed patients.
However, even immunity from vaccination is not lifelong. With an interest in the short-lived nature of vaccines, scientists are studying the course of protection in COVID-19 vaccinated and whether they are protected against mutated strains of the virus, sometimes more dangerous and contagious. For example, the American pharmaceutical company Moderna is developing new vaccines tailored specifically for the treatment of SARS-CoV-2 coronavirus mutations.
So what should we keep in mind? With the pandemic still galloping, a remarkable number of cases and deaths every day, we must not relax and forget that the virus is still among us. Thus, protection measures such as the use of masks and social distances will remain part of our daily lives even after vaccination, as many people will not enjoy immune protection, natural or artificial. As experts point out, 'less risk of transmission does not mean no transmission at all'.
