Leading medical and pharmaceutical company Johnson & Johnson has reportedly announced that its COVID-19 vaccine Ad26.COV2.S has stimulated immune response with just a single dose. According to new clinical data, the company’s vaccine candidate was able to provoke immune response that lasted for over two months, or 71 days, among 805 trial participants.
Reportedly, other approved vaccines for COVID-19 from Pfizer and Moderna involve two inoculations within a few weeks for full benefit and receiving only single shot would result in lesser immunity.
Johnson & Johnson has claimed that only one shot of its Ad26.COV2.S vaccine elicits strong neutralizing antibodies in more than 90% of its clinical trial volunteers. These neutralizing antibodies further work towards preventing the bonding of virus proteins with human cells. The company further stated that a two-dose procedure was less reactogenic, however, it triggered twice the amount of antibodies.
Apparently, upcoming phase three clinical trials that are also the final stage of vaccine testing are likely to ascertain if a second dose will offer additional effectiveness or durability, especially in elderly people.
The published report has stated that while all ongoing phase 3 trials of other Covid-19 vaccines have measured two-dose schedules, a single Ad26.COV2.S dose generated a strong humoral immune response among majority of vaccine recipients, with the availability of S-binding as well as neutralizing antibodies in over 90% of the participants, irrespective of age group or vaccine dose.
It has been reported that five adverse side effects were recorded with one participant being temporarily hospitalized for fever. Apart from fever, other common side effects that were reported are muscle pain, migraines, fatigue, and pain at the injection site.
Meanwhile, authors of the study have stated that as the U.S. government is facing challenges regarding the allocation of available doses of vaccine to the initial populations, a one-dose vaccine which has a proven outcome of being effective against COVID-19 will provide logistic advantages as compared to a two-dose vaccine, especially during a pandemic.
This is possibly due to the procedure of vaccine development. Apparently, using mRNA for communicating with human cells and equipping them against coronavirus pathogens, the Johnson & Johnson shot uses a weakened version of common cold known as adenovirus 26 for producing an immune response which will allow the body to recognize and resist particles of COVID-19.