Moderna covid vaccine produces neutralizing antibodies, enters final stage trial4 min read . Updated: 15 Jul 2020, 04:18 PM IST
Moderna’s Covid-19 vaccine produced antibodies to the coronavirus in all patients tested in an initial safety trial, federal researchers said, clearing an important milestone as the US continues to grapple with a surge in new infections
Moderna Inc.’s Covid-19 vaccine produced antibodies to the coronavirus in, all patients tested in an initial safety trial, federal researchers said, clearing an important milestone as the US continues to grapple with a surge in new infections.
The US biotech firm’s breakthrough is one of the most promising developments yet in the race to develop a vaccine against the virus that has paralyzed the world’s economy. Yet the road to a successful shot is filled with hurdles, and some patients in the trial experienced severe side effects.
“The good news is that this vaccine induced antibodies," said Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases. “Not just any kind of antibodies, but neutralizing antibodies."
Fauci, in a telephone interview, called the Moderna data “really quite promising." Though he said the side effects seen were not alarming and were typical of those experienced with other vaccines, some experts sounded a note of caution.
More than half of participants who got the middle of three doses administered in the trial suffered mild to moderate fatigue, chills, headache and muscle pain. Also, 40% of people in the middle-dose group experienced a fever after the second vaccination. Three of 14 patients given the highest dose experienced severe side effects, but that dose is not being used in larger trials.
“Man, that is a lot of adverse events," said Tony Moody, a doctor and researcher at the Duke Human Vaccine Institute. He said it would be “unusual" for a vaccine to have this rate of side effects.
On the plus side, Moody said that the antibody levels produced were “really encouraging." The neutralizing antibody levels in the trial produced were equivalent to the upper half of what’s seen in patients who get infected with the virus and recover, according to the results published Tuesday in the New England Journal of Medicine.
Moderna’s shares gained about 16% in US pre-market trading Wednesday. The stock has more than tripled in value this year on hopes that the company’s vaccine will gain rapid approval. The vaccine will move into a much larger late-stage trial later this month that’s likely to determine whether it’s fit for commercial use.
Although stimulating production of neutralizing antibodies doesn’t prove a vaccine will be effective, it’s considered an important early step in testing. The side effects reported weren’t severe enough in the majority of patients to preclude further testing, according to the report by researchers from the NIAID.
The vaccine news came as the pandemic continued thriving throughout the US Cases nationwide increased Tuesday to 3.4 million, according to data collected by Johns Hopkins University and Bloomberg News. More than 136,117 Americans have died.
While some states that suffered this spring have managed to quell the contagion, fierce hot spots are breaking out in the Sun Belt.
Moderna’s initial results are from the first group of 45 patients who received the vaccine, called mRNA-1273. It evaluated three doses that were given in a two-shot regimen. The middle one was selected for use in the large final-stage study that is slated to begin on July 27th.
In the trial, participants received the two shots 28 days apart. After the first dose, all of them generated antibodies that bound to the coronavirus, but most did not yet produce antibodies capable of neutralizing the virus.
But all 42 people who got both scheduled doses of the vaccine generated antibodies capable of neutralizing the coronavirus, according to the study results. The final-stage trial will compare the vaccine to placebo shots in 30,000 healthy people at high risk of coming down with the coronavirus.
One significant limitation of the data is it includes data only from the first 45 patients in the study, all of whom were from age 18 to 55. Results from a second portion of the phase 1 trial that included people older than this -- a key demographic for any Covid-19 vaccine, given the high death rate in older patients -- are not available yet.
William Haseltine, a former Harvard Medical School researcher who chairs Access Health International, said the levels of neutralizing antibodies produced were “respectable" and possibly protective. But he said “the jury is out" on safety of the vaccine.
Unlike traditional vaccines, which inject a weakened or inactivated virus or a piece of a virus to trigger an immune response, the Moderna product uses genetic material called messenger RNA to cause cells to produce the coronavirus spike protein. The goal is to produce antibodies to the virus that protect against the disease when someone is later exposed to the coronavirus.
The vaccine “clearly worked in that antibodies against the spikeprotein were generated, including antibodies that had virus neutralizing capability," said Paula Cannon, professor of microbiology at Keck School of Medicine of USC. A key question will be how long will the antibodies last before they start to wane, she said.
The initial findings from the Phase 1 trial are largely in line with top-line results Moderna published in a press release in May, but provide more details on the antibody levels produced and side-effects that were seen.
At the time, Moderna was criticized by some scientists for putting out a release describing positive results that temporarily drove up the company’s stock price, but included few numbers that would allow scientists to interpret the data.