On Friday, a team of Russian scientists published the first report on their Covid-19 vaccine, which had been roundly criticized because of President Vladimir Putin’s decision last month to approve it before clinical trials had proved it safe and effective.
In a small group of volunteers, the scientists found that the vaccine produced a modest level of antibodies against the coronavirus, while causing only mild side effects. The research has not yet shown, however, whether people who are vaccinated are less likely to become infected than those who are not.
In August, Mr. Putin announced with great fanfare that the vaccine — called Sputnik V — “works effectively enough” to be approved. He declared its approval to be a “very important step for our country, and generally for the whole world.”
But vaccine developers denounced the decision, observing that no data had been published on the vaccine. In addition, the critics pointed out, the Russian scientists had yet to run a large trial of tens of thousands of people, which is required to demonstrate that a vaccine works.
The new paper, published in the Lancet, contains the first batch of public data from Sputnik V’s clinical trials. Independent scientists were impressed by the rigor of the work.
“The science looks like it was done impeccably well,” said Naor Bar-Zeev of the Johns Hopkins Bloomberg School of Public Health, who is the co-author of a commentary on the new paper. Still, he cautioned that no one will know if Sputnik V is safe and effective until the larger trials are completed.
“We should welcome a Russian vaccine if it’s successful, and we should welcome other vaccines if they’re successful,” Dr. Bar-Zeev said. “But they should all be equally rigorously evaluated.”
Researchers at the Gamaleya Research Institute in Moscow used a design for the vaccine that they had previously developed and tested for MERS, a disease caused by another coronavirus.
The Sputnik V vaccine stimulates the immune system by coaxing a person’s cells to make a protein normally found on the coronavirus that causes Covid-19. The researchers loaded the gene for this viral protein into a second virus, called an adenovirus.
When injected into the arm, the adenovirus slips into muscle cells. It has been genetically engineered so that it cannot make copies of itself or cause illness. But once it delivers the coronavirus gene into a cell, the cell starts making the protein.
Similar adenovirus-based vaccines are also being tested by several other teams, including AstraZeneca, CanSinoBio and Johnson & Johnson.
Each team is testing a different strain of adenovirus. Unlike the rest, the Russian team is combining two adenoviruses into one vaccine. For their initial clinical trial, the Gamaleya researchers gave volunteers an initial shot of an adenovirus called Ad26, and then, three weeks later, a shot of one known as Ad5.
In the Lancet paper, the researchers said that they tested the vaccine on hamsters and monkeys. They claimed the animals were protected against the coronavirus without any harmful side effects but did not present any data about these studies in their new paper.
The trial they ran on human volunteers was what’s known as a Phase 1 / 2 trial. It was small: Only 40 volunteers received the full vaccine with both kinds of adenoviruses. No one received a placebo.
By comparison, the Chinese firm CanSinoBio ran a Phase 1 / 2 trial that included 382 people who received the vaccine and another 126 who were given a placebo.
The Russian vaccine produced mild symptoms in a number of subjects, the most common of which were fevers and headaches. Other adenovirus-based vaccines have produced similar side effects.
“You expect to have some symptoms — that’s normal,” Dr. Bar-Zeev said.
The researchers found that volunteers who received the full vaccine produced antibodies that could block the virus from replicating in cells.
To gauge the performance of their vaccine, the Russian researchers compared the level of antibodies with samples taken from people who had recovered from natural infections of Covid-19. Convalescent plasma, as these samples are known, contain antibodies to the virus that people make on their own.
In the paper, the researchers said that vaccinated people had the same levels of antibodies as those found in convalescent plasma.
Akiko Iwasaki, an immunologist at Yale University who was not involved in the study, said the vaccine produced “good antibody levels in all volunteers.”
But in a news release, the Gamaleya Institute implied that its vaccine was superior to AstraZeneca’s. It said that the level of antibodies from vaccinated volunteers was “1.4-1.5 times higher than the level of antibodies of patients who had recovered from Covid-19.”
AstraZeneca, they claimed, only produced antibody levels equal to that in convalescent plasma.
It is not clear why the paper presents a different picture. The authors of the study did not respond to a request for comment.
The Coronavirus Outbreak ›
Frequently Asked Questions
Updated September 4, 2020
What are the symptoms of coronavirus?
- In the beginning, the coronavirus seemed like it was primarily a respiratory illness — many patients had fever and chills, were weak and tired, and coughed a lot, though some people don’t show many symptoms at all. Those who seemed sickest had pneumonia or acute respiratory distress syndrome and received supplemental oxygen. By now, doctors have identified many more symptoms and syndromes. In April, the C.D.C. added to the list of early signs sore throat, fever, chills and muscle aches. Gastrointestinal upset, such as diarrhea and nausea, has also been observed. Another telltale sign of infection may be a sudden, profound diminution of one’s sense of smell and taste. Teenagers and young adults in some cases have developed painful red and purple lesions on their fingers and toes — nicknamed “Covid toe” — but few other serious symptoms.
Why is it safer to spend time together outside?
- Outdoor gatherings lower risk because wind disperses viral droplets, and sunlight can kill some of the virus. Open spaces prevent the virus from building up in concentrated amounts and being inhaled, which can happen when infected people exhale in a confined space for long stretches of time, said Dr. Julian W. Tang, a virologist at the University of Leicester.
Why does standing six feet away from others help?
- The coronavirus spreads primarily through droplets from your mouth and nose, especially when you cough or sneeze. The C.D.C., one of the organizations using that measure, bases its recommendation of six feet on the idea that most large droplets that people expel when they cough or sneeze will fall to the ground within six feet. But six feet has never been a magic number that guarantees complete protection. Sneezes, for instance, can launch droplets a lot farther than six feet, according to a recent study. It’s a rule of thumb: You should be safest standing six feet apart outside, especially when it’s windy. But keep a mask on at all times, even when you think you’re far enough apart.
I have antibodies. Am I now immune?
- As of right now, that seems likely, for at least several months. There have been frightening accounts of people suffering what seems to be a second bout of Covid-19. But experts say these patients may have a drawn-out course of infection, with the virus taking a slow toll weeks to months after initial exposure. People infected with the coronavirus typically produce immune molecules called antibodies, which are protective proteins made in response to an infection. These antibodies may last in the body only two to three months, which may seem worrisome, but that’s perfectly normal after an acute infection subsides, said Dr. Michael Mina, an immunologist at Harvard University. It may be possible to get the coronavirus again, but it’s highly unlikely that it would be possible in a short window of time from initial infection or make people sicker the second time.
What are my rights if I am worried about going back to work?
John Moore, a virologist at Weill Cornell Medicine in New York who was not involved in the study, said that it was too early to make any meaningful comparisons among the various Covid-19 vaccines. Each team uses different tests to measure antibody levels. And each group of recovered patients they study for convalescent plasma may have different levels of antibodies.
“We have long been suffering from the apples-versus-oranges scenario, but now we’re into fruit salad territory, and it drives me bananas trying to figure it all out,” he said.
One thing is clear, however: No Phase 1 / 2 trial can demonstrate protection against Covid-19.
That requires a so-called Phase 3 trial, in which a large number of volunteers are given either a vaccine or a placebo. A Phase 3 trial can also reveal harmful side effects missed by small preliminary studies.
In their paper, the Russian scientists wrote that they got approval on Aug. 26 to run a Phase 3 trial on 40,000 people. There are seven other vaccines currently in these late-stage trials. Johnson & Johnson is expected to start its own Phase 3 trial later this month, and Novavax is expected to start its own in October, bringing the total to 10.
Phase 3 trials can take months to yield clear results, Dr. Bar-Zeev said, and even then they have to be carefully reviewed before any decision is made about using a vaccine widely.
“Yes, we all want a vaccine, but we don’t want to make a mistake,” he said. “So hang in there and wait, so we know what we’re getting into.”
Andrew Kramer contributed reporting from Moscow.