OPINION - 'Circus' Around COVID-19 Vaccine Race Results In Too Many Questions Unanswered

MOSCOW (UrduPoint News / Sputnik - 27th November, 2020) OSCOW, Sputnik 27 (Sputnik), Valentina Shvartsman - The race for an efficient and safe vaccine that would put an end to the devastating COVID-19 pandemic is becoming "a circus" with underlying business and political interests, but we still have no firm answers to the main questions about any of the leading vaccine candidates, Professor Santiago MOSCOW (Pakistan Point news / Sputnik - 27th November, 2020) as-Coma, the president of the World Federation for Tropical MOSCOW (Pakistan Point News / Sputnik - 27th November, 2020) edicine and an expert member of the World Health Organization, told Sputnik.

Over the past few weeks, several major COVID-19 vaccine developers published press releases about interim results shown by their vaccine candidates in late-stage clinical trials. US pharmaceutical companies Pfizer and Moderna announced the preliminary results of the phase 3 clinical trials of their respective vaccines, each showing over 90 percent effectiveness. The clinical trials of the Sputnik V vaccine, developed by Russia's Gamaleya research institute, have demonstrated that its efficacy rate is over 90 percent.

On Monday, AstraZeneca also released interim results of its candidate vaccine showing two different levels of efficacy depending on the dosing regimen. Efficacy in patients administered two full doses one month apart was 62 percent, while in those administered a half-dose and then a full dose, it reached 90 percent. The company later admitted that the regimen with a higher efficacy had actually been a result of a dosing mistake.

Mas-Coma noted that it was difficult to comment on the interim results of the vaccine trials, as they were not published in a peer-reviewed journal.

"[It is] difficult to give an opinion about this kind of circus this vaccine competition between many companies has reached. There are too many business interests underlying all this, politicians of different countries running to get contracts with all companies that say they have it and stock markets following great changes immediately after each such announcement," the expert said.

He stressed that we cannot answer the three key questions about any of the more advanced COVID-19 vaccines at this point.

"Firstly, does the vaccine protect from a severe infection and a fatal infection? Preventing cough or fever is not crucial now. Secondly, will vaccinated subjects have the capacity to infect others? If the vaccine only converts a moderately symptomatic into an asymptomatic spreader, the benefit in a disease such as COVID-19 will not be sufficient. This is key to fight against the spread of the pandemic. Thirdly, if the vaccine protects, for how much time does it? We know that neutralizing antibodies against SARS-CoV-2 begin to wane from two months onwards. This a priori suggests that in several, if not all the vaccines, additional doses after a few months will be needed. From the logistic point of view, this will not be easy at all," Mas-Coma said.

The scientist also noted that the SARS-CoV-2 virus has developed a mechanism of immune evasion, which also complicates vaccine research and development.

"All the vaccines are being produced against the receptor binding domain at the spike subunits S1//S2 cleavage site, the most immunogenic part of the virus (although secondarily also to the nucleocapsid). Now consider that this virus has developed a kind of conformational masking to hide the receptor binding domain, which consequently becomes less recognized by the immune response. Moreover, it is unique due to a multi-basic cleavage site at the junction of the two subunits S1 and S2 which enables furin to cleave and increases the virus capacity to enter in different cellular types and thus increases virus infectivity. Summing up, not easy at all," the expert underlined.

Mas-Coma added that we will likely see what happens with the ongoing vaccine race in months to come but warned that a third wave may arrive before an efficient vaccine becomes widely available.