An experimental coronavirus vaccine developed by Moderna induced immune responses in all clinical trial participants without any major side effects, scientists have reported.
The results of the Phase 1 trial conducted in conjunction with the National Institute of Allergy and Infectious Diseases were published Tuesday in the New England Journal of Medicine.
During the open-label trial, 45 healthy adults between the ages of 18 and 55 received two vaccinations spaced 28 days apart in March and April.
The scientists found that after just the first vaccination, antibody responses were higher with groups that received a higher dose.
After receiving both rounds of vaccines, scientists noted participants had high levels of “virus-neutralizing activity capable of reducing SARS-CoV-2 infectivity.”
More than half of the participants experienced systemic and local side effects such as fatigue, chills, headache, myalgia and pain at the injection site.
Three people didn’t receive the second dose — one experienced a skin reaction after the first vaccine and two missed the second vaccination window.
Although trial participants developed antibodies in response to the vaccine, it does not necessarily mean the vaccine works; a third phase of the clinical trial will be required.
“These positive Phase 1 data are encouraging and represent an important step forward in the clinical development of mRNA-1273, our vaccine candidate against COVID-19, and we thank the NIH for their ongoing collaboration,” Moderna Chief Executive Officer Stéphane Bancel said in a news release.
Chief Medical Officer Tal Zaks added, “We look forward to beginning our Phase 3 study of mRNA-1273 this month to demonstrate our vaccine’s ability to significantly reduce the risk of COVID-19 disease.”
Moderna has received over $500 million from the government to develop its vaccine, and released partial results of the trial in May, Politico reported.
Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, expressed “cautious optimism” regarding the initial Moderna results.
“Having looked at the data myself, it is really quite promising,” Fauci told NPR.
“The vaccine induced what we call neutralizing antibodies, as opposed to just binding antibodies, and neutralizing antibodies are antibodies that actually can block the virus.”
Moderna plans to start a Phase III trial on July 27 and will eventually enroll 30,000 people, Politico reported.
As of July 15, there are 23 coronavirus vaccine candidates in clinical trials, according to the World Health Organization.
As of Wednesday, there were 13.3 million cases of coronavirus worldwide and 579,546 deaths, according to data from Johns Hopkins.
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