Pfizer Inc said on Monday it has started a mid-to-late-stage study testing its investigational oral antiviral drug for the prevention of COVID-19 infection among those who have been exposed to the virus.
The company and its rivals, including U.S.-based Merck & Co Inc and Swiss pharmaceutical Roche Holding AG, have been racing to develop the first antiviral pill for COVID-19.
Pfizer said it would study the drug, PF-07321332, in up to 2,660 healthy adult participants aged 18 and older who live in the same household as an individual with a confirmed symptomatic COVID-19 infection.
The trial would test PF-07321332 with a low dose of ritonavir, an older medication widely used in combination treatments for HIV infection.
Merck and partner Ridgeback Biotherapeutics said earlier this month they had begun enrolling patients in a late-stage trial of their experimental drug molnupiravir for prevention of COVID-19 infection.
Frequently Asked Questions
A vaccine works by mimicking a natural infection. A vaccine not only induces immune response to protect people from any future COVID-19 infection, but also helps quickly build herd immunity to put an end to the pandemic. Herd immunity occurs when a sufficient percentage of a population becomes immune to a disease, making the spread of disease from person to person unlikely. The good news is that SARS-CoV-2 virus has been fairly stable, which increases the viability of a vaccine.
There are broadly four types of vaccine — one, a vaccine based on the whole virus (this could be either inactivated, or an attenuated [weakened] virus vaccine); two, a non-replicating viral vector vaccine that uses a benign virus as vector that carries the antigen of SARS-CoV; three, nucleic-acid vaccines that have genetic material like DNA and RNA of antigens like spike protein given to a person, helping human cells decode genetic material and produce the vaccine; and four, protein subunit vaccine wherein the recombinant proteins of SARS-COV-2 along with an adjuvant (booster) is given as a vaccine.
Vaccine development is a long, complex process. Unlike drugs that are given to people with a diseased, vaccines are given to healthy people and also vulnerable sections such as children, pregnant women and the elderly. So rigorous tests are compulsory. History says that the fastest time it took to develop a vaccine is five years, but it usually takes double or sometimes triple that time.