Drug manufacturers and research centers around the world are working on COVID-19 vaccines, with large global trials of several of the candidates involving tens of thousands of participants already underway. Some companies had suggested that the first test data could be ready for release in October, but have since postponed it to November and December.
Here’s what we know about the race to deliver vaccines to help end the coronavirus pandemic that has claimed more than a million lives around the world:
Who is further ahead?
US pharmaceutical company Pfizer Inc with its German partner BioNTech SE, and US company Biotech Moderna Inc could have initial data in November. Britain-based AstraZeneca Plc, along with the University of Oxford, and Johnson & Johnson say they are on track to deliver data for their vaccines this year.
What happens in these trials?
The companies are testing their vaccines against a placebo, usually saline, in healthy volunteers to see if the rate of COVID-19 infection among those who received the vaccine is significantly lower than among those who received the dummy injection.
Why are the data reports lagging beyond the original predictions?
The trials are based on subjects being naturally infected with the coronavirus, so the time it takes to generate results depends largely on how widespread the virus is where the trials are conducted. Each pharmacist has targeted a specific number of infections to trigger a first analysis of their data.
Pfizer, for example, thinks it can tell if its vaccine works once 32 people contract COVID-19 in the 44,000-person trial, provided the vast majority of those infected have received the placebo.
But drug makers have said that an insufficient number of infections before recent spikes in cases slowed their ability to present data earlier. In October, Pfizer said it did not expect to have usable test data until the end of November due to slow infection rates. He had previously suggested that it would happen in October.
AstraZeneca said a slowdown in infections over the summer delayed its trial in the UK and it hoped to see results by the end of the year. His schedule was also extended with a hiatus to investigate illness in a trial participant from the UK.
After a slowdown in infections in the late summer and early fall, COVID-19 cases became rampant again in October and early November, setting daily records in the United States and Europe as the weather cooled and people moved indoors. Experts have suggested that trial participants may also have been more careful to avoid contracting COVID-19 than the general population knowing that they may have received a placebo.
How will we know if the vaccine works?
The United States, the European Union, the United Kingdom, and the World Health Organization have set similar minimum standards of efficacy. Some regulators have said that vaccines must demonstrate at least 50% efficacy – that is, at least twice as many infections among volunteers who received a placebo than among those in the vaccine group. The European Medicines Agency has said it can accept a lower level of efficacy.
When will regulators decide?
Regulators will review vaccines after companies have enough data to submit requests for emergency use authorization (EUA) or formal approval. The earliest they could decide is December because Moderna and Pfizer / BioNtech don’t expect to have enough safety data until the second half of November. US regulators have called for participants to be monitored for two months after receiving a final dose of the vaccine for side effects. AstraZeneca could provide a look at the last stage data by the end of the year. UK officials said there is a slim chance they could decide on that vaccine by the end of December.
Regulators in Europe, the UK and Canada are considering the data on an ongoing basis, as it becomes available. They hope to do quick reviews of the initial data for possible emergency use before the longer, more traditional reviews for formal business approvals.
Could these be the first approved coronavirus vaccines?
Yes, although China and Russia are on a similar timeline. China launched an emergency use program in July targeting essential workers and others at high risk of infection that has vaccinated hundreds of thousands of people. At least four vaccines are far behind, including those from the China National Biotec Group (CNBG), CanSino Biologics and Sinovac. Sinovac and CNBG have said they expect the first test data from November. Russia’s Gamaleya Institute has started a 40,000-person last-stage trial and is expected to have initial data in November. Russia has also administered the vaccine to at least hundreds of “high-risk” members of the general population.
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