Pfizer’s experimental coronavirus vaccine caused antibody levels up to THREE TIMES higher than those observed in recovered patients, early data shows
- Researchers randomly gave 45 healthy volunteers a low dose, medium dose, or high dose of a coronavirus vaccine or placebo
- Those who received the vaccine received two shots, except for the high-dose group after half the fever
- The vaccine generated levels of neutralizing antibodies that were between 1.8 and 2.8 times higher than those in recovered patients
- No life-threatening side effects were seen and Pfizer hopes to start a large-scale human trial later this summer
An experimental coronavirus vaccine being tested by Pfizer Inc and its German partner BioNTech showed encouraging early results, the companies announced Wednesday.
The trial recruited 45 people who received a low, medium or high dose of the vaccine in two shots or a placebo.
Volunteers who received the low or medium dose had immune responses in the range expected to be protective, according to the preliminary findings, compared to COVID-19 survivors.
The results are published on the pre-print site medRxiv.org, have been submitted for publication in a scientific journal, but have not yet been peer-reviewed.
Researchers randomly gave 45 healthy volunteers a low dose, a medium dose, or a high dose of a coronavirus vaccine or a placebo. Pictured: The first patient to participate in the clinical trial of Pfizer’s COVID-19 vaccine at the University of Maryland School of Medicine in Baltimore received an injection on May 4
Those who received either two shots of the low or medium dose of the vaccine generated levels of neutralizing antibodies between 1.8 and 2.8 times higher than those in recovered patients (above)
“We still have a way to go and we are also testing other candidates,” said Philip Dormitzer, Chief Scientific Officer for Viral Vaccines at Pfizer’s research labs. STAT News.
“What we can say at this point is that there is a viable candidate based on immunogenicity and safety data on early tolerance.”
Pfizer and Biotech’s vaccine candidate uses part of the genetic code of the pathogen to help the body recognize the coronavirus and attack if a person becomes infected.
For the study, three groups of 12 received a 10 microgram dose, a 30 microgram dose, or a 100 microgram dose. Nine received a placebo.
The highest dose shot caused fever in about half of the group, so a second shot was not given.
Three weeks later, participants received a second dose. Thereafter, 8.3 percent of the 10 microgram group and 75 percent of the 30 microgram group reported fever.
However, these side effects did not result in hospitalization, were not considered life-threatening, and resolved after about a day.
The immunization not only generated antibodies to the virus, but specifically neutralized antibodies, meaning they prevent the virus from infecting human cells.
The results showed that levels of neutralizing antibodies were between 1.8 and 2.8 times higher than those in recovered patients.
Volunteers who received one 100 microgram dose had lower antibody levels than those who received two shots of the low or medium dose.
After news of the preliminary results, Pfizer’s shares rose by four percent on Wednesday.
The American pharmaceutical giant hopes to start a large-scale trial this summer, but has not indicated which injection it will test.
About 200 vaccines are being developed worldwide, of which more than 15 are currently being tested in humans at a later stage, such as AztraZeneca in collaboration with the University of Oxford, Inovio and Moderna.
A number of pharmaceutical companies are expected to begin human trials later this summer, including Johnson & Johnson, Merck and Sanofi.