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How many vaccines are in preparation?
The World Health Organization (WHO) has identified 42 “candidate vaccines” in clinical trials, up from 11 in mid-June.
Ten of them are at the very advanced stage of the “phase 3” trial, where the efficacy of the vaccine is being tested on a large scale, usually in tens of thousands of people on several continents.
The American Modern Biotechnology Company, an American-German collaboration between BioNTech and Pfizer, several Chinese state-controlled pharmaceutical laboratories, and a European project coordinated by the University of Oxford and AstraZeneca are among the most promising players involved in the race of the vaccinations
What kind of vaccines?
Some methods of obtaining a vaccine have already been tested over time and others remain experimental.
Inactivated “classic” vaccines use a viral corpuscle that has been inactivated, “killed,” while others use weakened or “attenuated” viral strains that are still virulent enough to trigger antibody production but do not cause disease.
So-called “subunit” vaccines contain a fragment derived from the pathogen to produce an appropriate immune response.
Strains of “viral vectors” use other forms of “live” viruses to transmit DNA to human cells, triggering an immune response. For example, a measles virus, modified with a specific protein from the new coronavirus, can be used against COVID-19.
There are also experimental gene-based vaccines that use DNA or RNA fragments.
What are the results?
To date, only Phase 1 and Phase 2 test results have been published in peer-reviewed medical journals and journals.
Preliminary results showing that the vaccine developed by the Chinese company Sinopharm induces an immune response were published in The Lancet on Friday.
Similar studies have shown in recent weeks the development of one of the Russian vaccines, as well as that of the Oxford University vaccine, the vaccine created by the Chinese company CanSino and that of Moderna.
Although the preliminary results are encouraging, it is too early to know if these vaccines will be successful. Testing for two candidate vaccines, produced by Johnson & Johnson and Eli Lilly, has been temporarily halted due to safety concerns.
But this isn’t necessarily bad news, says Stephen Evans, professor of pharmacoepidemiology at the London School of Hygiene and Tropical Medicine.
“The fact that these tests have been temporarily stopped shows that there must be confidence that the entire process of monitoring the safety of the test participants is working properly,” he said.
Recent cases, in which patients cured of COVID-19 were infected a second time with a new strain, raise questions about how long vaccinated people will be protected.
Speed vs. safety
Companies backed by the governments of China, Russia and the United States are competing to be the first to cross the finish line.
In early August, Russian President Vladimir Putin proclaimed victory and announced the Sputnik V vaccine before the third phase of testing began. But few outside of Russia have agreed to test the vaccine, and experts say Putin’s announcement was premature.
Donald Trump promised a vaccine before the November 3 election, but it is unlikely that he will be able to keep his word. Earlier this month, the United States Food and Drug Administration (FDA) announced that it would need the data collected up to 2 months after vaccination before issuing an emergency authorization to use a vaccine. And on Friday, Pfizer announced that its vaccine won’t be ready until mid-November.
“What is different about COVID-19 vaccines is that the speed of potential development and approval is much faster due to the public health emergency,” the European Medicines Agency noted. But not even this pressing need can be used to invoke rule-breaking.
“Before approval, all vaccines in the European Union are evaluated to the same high standards as any other drug,” according to a statement from the European Medicines Agency.
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