>>Denise Grady, The New York Times
Published: 2020-05-18 19:36:34 BdST
The findings are based on results from the first eight people who each received two doses of the experimental vaccine, starting in March.
Those people, healthy volunteers ages 18 to 55, made antibodies that were then tested in infected cells in the lab and were able to stop the virus from replicating — the key requirement for an effective vaccine. The levels of those so-called neutralising antibodies matched or exceeded the levels found in patients who had recovered after contracting the virus in the community.
Though encouraging, the findings do not prove that the vaccine works. Only larger, longer studies can determine whether it can actually prevent people in the real world from getting sick. Moderna’s technology, involving genetic material from the virus called mRNA, is relatively new and has yet to produce any approved vaccine.
Early results from a handful of test subjects may not seem like much to go on, but the world is desperate for good news. With the highly contagious virus defying most efforts to control its spread, vaccines are seen as the best and perhaps only hope of stopping or even slowing a pandemic that has sickened nearly 5 million people worldwide, killed 315,000 and locked down entire countries, paralysing their economies.
Moderna produced the vaccine in collaboration with the National Institute of Allergy and Infectious Diseases, the institute led by Dr. Anthony Fauci, which has been leading the clinical trials. That institute, a part of the federal National Institutes of Health, is also involved in research on other experimental coronavirus vaccines.
The news helped buoy Wall Street, rallying the markets. In recent months, Moderna’s stock has soared as it pursued a vaccine, and it was up more than 25% by midafternoon Monday.
Dozens of other companies and universities are also rushing to create coronavirus vaccines, and several have also begun to test their candidates in human subjects, including Pfizer and its German partner BioNTech; Chinese company CanSino; and the University of Oxford, working with AstraZeneca.
Experts agree that it is essential to develop multiple vaccines because the urgent global need for billions of doses will far outstrip the production capacity of any one manufacturer.
At the same time, there is widespread concern that haste could compromise safety, resulting in a vaccine that does not work or even harms patients. Vaccines have generally taken years, sometimes a decade or more, to reach the market. A significant part of that time is taken up by large trials in thousands of subjects, waiting to see if the vaccine prevents infection and making sure that it does not make the illness worse — a known, though uncommon effect called disease enhancement.
Moderna’s early stage of testing, phase one, is continuing, Two more age groups, 55 to 70, and 71 and older, are now being enrolled to test the vaccine.
The actual data from these preliminary tests has not been published or shared publicly but has been submitted to the Food and Drug Administration, which does not comment on trials still in progress. The company said it hoped to make data publicly available this summer, when its final stage of testing is due to begin.
Moderna has said that it is proceeding on an accelerated timetable, with the second phase involving 600 people to begin soon, and a third phase to begin in July involving thousands of healthy people. The Food and Drug Administration gave Moderna the go-ahead for the second phase earlier this month.
If those trials go well, a vaccine could become available for widespread use by the end of this year or early 2021, said Dr. Tal Zaks, Moderna’s chief medical officer. How many doses might be ready is not clear, but Zaks said, “We’re doing our best to make it as many millions as possible.”
Two shots, four weeks apart, are likely to be needed, meaning that however many doses are produced, only half that number of people can be vaccinated.
There is no proven treatment or vaccine against the coronavirus at this time. Dozens of companies in the United States, Europe and China are racing to produce vaccines, using different methods. Some use the same technology as Moderna, which involves a segment of genetic material from the virus called messenger RNA, or mRNA.
Moderna said that additional tests in mice that were vaccinated and then infected found that the vaccine could prevent the virus from replicating in their lungs and that the animals had levels of neutralising antibodies comparable to those in the people who had received the vaccine.
Three doses of the vaccine were tested: low, medium and high. These initial results are based on tests of the low and medium doses. The only adverse effect at those doses was redness and soreness in one patient’s arm where the shot was given.
But at the highest dose, three patients had fever, muscle pains and headaches, Zaks said, adding that the symptoms went away after a day.
But the high dose is being eliminated from future studies, not so much because of the side effects but because the lower doses appeared to work so well that the high dose is not needed.
“The lower the dose, the more vaccine we’ll be able to make,” Zaks said.
Moderna uses genetic material — messenger RNA — to make vaccines, and the company has nine others in various stages of development, including several for viruses that cause respiratory illnesses. But no vaccine made with this technology has yet reached the market.
Work on the new coronavirus started in January, as soon as Chinese scientists posted its genetic sequence on the internet. Researchers at Moderna and the National Institute of Allergy and Infectious Diseases identified part of the sequence that codes for a spikelike protein on the surface of the virus that attaches to human cells, helping the virus to invade them.
The idea behind Moderna’s vaccine is to inject the mRNA for part of the spike protein and have it slip into the cells of a healthy person, which then follow its instruction and crank out the viral protein. That protein should act as a red flag for the immune system, stimulating it to produce antibodies that will prevent infection by blocking the action of the spike if the person is exposed to the virus.
©2020 The New York Times Company