Story at a glance
- Clinical trials suggest that Johnson & Johnson’s COVID-19 vaccine provokes an immune response with one vaccination, as opposed to others already available.
- The company still has to complete phase three clinical trials.
New clinical data suggests that Johnson & Johnson's COVID-19 vaccine candidate was able to stimulate an immune response that lasted for a little over two months, or 71 days, among 805 study participants.
Announced via a press release and published in The New England Journal of Medicine, the company said its vaccine, called Ad26.COV2.S, provoked an immune response against COVID-19 antibodies after a single dose.
Other approved COVID-19 vaccines from Pfizer and Moderna require two inoculations within a few weeks for the full benefit. To receive only a single shot would result in less immunity.
Johnson & Johnson claims that only one shot of Ad26.COV2.S elicits strong neutralizing antibodies in more than 90 percent of its clinical trial volunteers.
These neutralizing antibodies work to stop virus proteins from bonding with human cells. A two-dose regimen was less reactogenic, but triggered double the antibodies.
Upcoming phase three clinical trials, the final stage of vaccine testing, will confirm if a second dose will provide additional efficacy or durability benefits, primarily in elderly people.
“Although all ongoing phase 3 studies of other Covid-19 vaccines have assessed two-dose schedules, a single dose of Ad26.COV2.S elicited a strong humoral response in a majority of vaccine recipients, with the presence of S-binding and neutralizing antibodies in more than 90% of the participants, regardless of either age group or vaccine dose,” the published report read.
Five serious adverse side effects were reported, including one participant temporarily hospitalized with a fever. Other common adverse effects were migraines, muscle pain, fatigue and pain at the injection site.
As the U.S. government struggles to allocate available vaccine doses to initial populations, a single-dose vaccine that proves effective against COVID-19 exposure “has obvious logistic advantages over a two-dose vaccine, especially during a pandemic,” per the study authors.
This may be due to how the vaccine is made. CNN notes that rather than using mRNA to communicate with human cells and arm them against COVID-19 pathogens, Johnson & Johnson’s candidate features a weakened version of the common cold called adenovirus 26 to elicit an immune response to help the body recognize and fight COVID-19 particles.
Johnson & Johnson notably acknowledged that a lack of minority groups characterized the representation of study participants.
Despite the promising results in early trials, The New York Times writes that the company is behind production, leaving the federal government waiting on more than 60 million doses. The company reportedly may be able to catch up production by March.