A coronavirus vaccine tested in 108 healthy volunteers in China safely triggered an immune response in the participants, a new study reveals.
The antibody production in the patients is a good sign that the vaccine may protect them from infection, but it is too early to say with certainty.
The Chinese vaccine was the first ever shot to enter clinical trials earlier this year – months before human tests for the UK candidate candidate shot – made by Oxford University – or the U.S. lead candidate, made by biotech Moderna.
Most people who received the vaccine had immune responses, although their level of antibodies thought to neutralize the virus was relatively low. Researchers saw a stronger increase in other immune compounds called T cells, which may also help fight the infection.
There were side effects – mainly pain, muscle aches and fever – but resolved within 28 days and no serious or dangerous side effects were reported.
Promising results from the completed first human Ad5 coronavirus vaccine in China put it ahead of the global race for a shot, although only by a small margin, an expert told DailyMail.com.
Chinese researchers are the first to conduct a human trial for a coronavirus vaccine, which was safe and caused an immune response in the participants, but an American expert fears that the shot did not produce enough ‘neutralizing’ antibodies to block infection (resistant)
The study, conducted by the collaborating universities and local CDCs in China, recruited 108 patients aged 18 to 60 and divided them into three groups of low, medium and high doses of the vaccine received, respectively
At the start of the study, none of the patients – who had never been infected with coronavirus – had neutralizing antibodies to SARS-CoV-2, the virus that causes COVID-19.
Within two weeks, researchers began to see signs that their antibody levels increased ‘moderately’ and peaked 28 days after the volunteers took their shots, according to the study published Friday The Lancet.
The levels of neutralizing antibodies – a type of immune cell that binds to a virus and may be able to completely block the infection – were more than twice as high among the participants who received the high dose, compared to those who received the low dose.
While any increase in neutralizing antibodies was a significant gain over the subjects’ starting levels (zero), Dr. Peter Hotez, a vaccine expert at Baylor College of Medicine in Texas, was not impressed with the levels produced in the test participants.
“All we don’t see is a very high neutralizing antibody titer,” he told DailyMail.com.
“The question is whether we will need it and whether these vaccines are enough to stimulate an immune response.”
Patients in the trial had more robust increases in their level of T cells, immune cells that perform a search and destruction function, rather than the blocking work done by neutralizing antibodies.
More studies will be needed to determine whether the vaccine can protect against infection in practice.
It is encouraging that none of the 108 patients had serious side effects.
More than 80 percent did have some side effects, but they were usually mild or moderate, such as muscle pain, fever, and pain. Most disappeared within a few weeks and almost all had disappeared by the end of the study.
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“That’s pretty good,” says Dr. Hotez.
Side effect profiles can be particularly important in getting people vaccinated against coronavirus as soon as one is available.
A Reuters survey published Thursday found that a quarter of Americans were not very much or not at all interested in getting a vaccine for the virus that infected more than 1.6 million people in the US.
Many of them said they feared the vaccine would be more risky than the disease itself, because development is so rapid.
So far, the US government is supporting the development of 14 candidate vaccinations through its Operation Speed initiative.
It is unclear whether the US is coordinating with Chinese vaccine developers.
In the US and UK, vaccines from Moderna and Oxford University (in collaboration with AstaZeneca) are in human trials and have shown promising early results.
China’s completed trial puts it first – but not much, Dr. Hotez says. He says that all vaccines must go through large phase III studies before they become available, bringing their timelines closer together.