Author(s): Ewen Callaway
Coronavirus vaccine trials have delivered their first results -- but their promise is still unclear
Vaccines against the coronavirus are being tested in humans and animals. [see PDF for image]
Credit: Juan Ignacio Roncoroni/EPA-EFE/Shutterstock
A nurse wearing PPE gives a vaccine against flu.
As coronavirus vaccines hurtle through development, scientists are getting their first look at data that hint at how well https://www.nature.com/articles/d41586-020-01221-y . The picture, so far, is murky.
On 18 May, US biotech firm Moderna revealed the first data from a human trial: its COVID-19 vaccine triggered an immune response in people, and protected mice from lung infections with the coronavirus SARS-CoV-2. The results -- which the company, based in Cambridge, Massachusetts, announced in a https://investors.modernatx.com/news-releases/news-release-details/moderna-announces-positive-interim-phase-1-data-its-mrna-vaccine -- were widely interpreted as positive and sent stock prices surging. But some scientists say that because the data haven't been published, they lack the details needed to properly evaluate those claims.
Tests of other fast-tracked vaccines show that they have prevented infections in the lungs of monkeys exposed to SARS-CoV-2 -- but not in some other parts of the body. One -- a vaccine being developed at the University of Oxford, UK, that is also in human trials -- protected six monkeys from pneumonia, but the animals' noses harboured as much virus as did those of unvaccinated monkeys, researchers reported1 last week in a bioRxiv preprint. A Chinese group reported similar caveats about its own vaccine's early animal tests this month2 .
Despite uncertainties, all three teams are pressing ahead with clinical trials. These early studies are meant mainly to test safety, but larger clinical trials designed to determine https://www.nature.com/articles/d41586-020-01247-2 from COVID-19 could report in the next few months.
Still, the early data offer clues as to how coronavirus vaccines might generate a strong immune response. Scientists say that animal data will be crucial for understanding how coronavirus vaccines work, so that the most promising candidates can be identified quickly and then refined. "We might have vaccines in the clinic that are useful in people within 12 or 18 months," says Dave O'Connor, a virologist at the University of Wisconsin-Madison. "But we're going to need to improve on them to develop second- and third-generation vaccines."
Moderna's vaccine, which is being co-developed with the US National Institute of Allergy and Infectious Diseases (NIAID) in Bethesda, Maryland, began safety testing in humans in March. The vaccine consists of mRNA...