Washington (AFP) – US biotech firm Moderna said Tuesday that it will enter the final stage of human testing for its COVID-19 vaccine on July 27, to assess how well it protects people in the real world.
The announcement came when the results of an earlier trial to show that the vaccine was safe and the production of activated antibodies were published.
The next Phase 3 trial will recruit 30,000 participants in the United States, with half to receive the vaccine at dose levels of 100 micrograms and the other half to receive a placebo.
The researchers will then track them for two years to determine if they are protected against infection by the virus. Or, if they become infected, if the vaccine prevents symptoms from developing.
If they have symptoms, the vaccine can still be considered a success if it stops severe cases of COVID-19.
The study should run until October 27, 2022, but preliminary results should be available much sooner.
The announcement came shortly after the New England Journal of Medicine published the results of the first stage of the Moderna vaccine trial, which showed that the first 45 participants developed antibodies against the virus.
Moderna is considered to be in a leading position in the global race to find a vaccine against the coronavirus, which has infected more than 13.2 million people and killed 570,000.
But scientists caution that the first vaccines to hit the market may not be the most effective or safest.
– Encouraging results –
Moderna had previously released “provisional results” from the early stages of its test, called Phase 1 in May.
The first results were called “encouraging” by Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases, which is jointly developing the vaccine.
But some in the scientific community said they would reserve judgment until they saw the full results in a peer-reviewed way.
According to the document, 45 participants were divided into three groups to test doses of 25 micrograms, 100 micrograms, and 250 micrograms.
They were given a second dose of the same amount 28 days later.
After the first round, antibody levels were found to be higher with higher doses.
After the second round, participants had higher levels of antibodies than most patients who had had COVID-19 and had generated their own antibodies.
More than half of the participants experienced mild or moderate side effects, which is considered normal.
Side effects included fatigue, chills, headache, body aches, and injection site pain.
Three participants did not receive their second dose.
They included one who developed a rash on both legs, and two who missed the window because they had COVID-19 symptoms, but their tests later came back negative.
Amesh Adalja, an infectious disease specialist at Johns Hopkins University, said it was encouraging that participants developed high levels of an advanced class of antibodies.
However, he added: “You must be very limited in how much you can extrapolate from a phase one clinical trial because you want to see how this works when a person is exposed to the real virus.”
The Modern vaccine belongs to a new class of vaccine that uses genetic material, in the form of RNA, to encode the information necessary to cultivate the spike protein of the virus within the human body, in order to trigger an immune response.
The spike protein is a part of the virus that it uses to invade human cells, but by itself the protein is relatively harmless.
The advantage of this technology is that it avoids the need to manufacture viral proteins in the laboratory, which helps to increase mass production.
No vaccine based on this platform has previously received regulatory approval.
Initial work using this technology was counterproductive in making the hosts more, rather than less, susceptible to infection, David Lo, a professor of biomedical science at the University of California Riverside, told AFP.
“One of the things that we certainly want to consider is whether there is a long-term effect in which the immune response … potentially develops an immune tolerance that would actually be detrimental to protection,” he said.
