The company expects to report details on more advanced trials later this month and hopes to apply for permission from the U.S. Food and Drug Administration shortly thereafter.
Researchers who tested the vaccine in a combined phase 1-2 trial – mostly intended for safety – found either one or two doses of the vaccine generated both antibody and T cell responses to coronavirus. The trials were not designed to show whether the vaccine protected humans against either infection or symptoms of coronavirus – that’s what the ongoing Phase 3 trials are designed to do.
The researchers ̵
Vaccination elicited neutralizing antibodies – expected to stop the virus from infecting cells – in 90% of all participants on the 29th day after the first vaccine dose and in all of them two months after the first dose. The levels of these antibodies remained stable for at least 71 days, they reported.
The FDA has granted emergency use for two coronavirus vaccines – one made by Pfizer with its partner BioNTech and another by Moderna. Both were approx. 95% effective in preventing symptomatic disease in their phase 3 trials. They use messenger RNA or mRNA – a new vaccine technology.
Johnson & Johnson’s vaccine arm, Janssen, uses a different approach to its vaccine, now called by its experimental name, Ad26.COV2.S. It uses an attenuated version of a cold virus called adenovirus 26 to carry genetic material from the virus into the body, causing human cells to produce pieces of the virus, which are then recognized by the immune system.
“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 participants, regardless of age group or vaccine dose,” the researchers wrote.
“An effective single-dose Covid-19 vaccine has obvious logistical advantages over a two-dose vaccine, especially during a pandemic.” The company is investigating whether another dose increases the effectiveness or shelf life of the immune response.
Side effects included headaches, body aches and more often fever.
“The company expects to publish topline phase 3 data for its single-dose Janssen COVID-19 vaccine candidate by the end of January 2021; as this trial is dependent on disease events, the timing is approximate,” Johnson & Johnson said in a statement. But with the pandemic raging in the United States and Europe, vaccine experts say, the answers come quickly to vaccine trials.
“If it turns out that the single-dose vaccine is safe and effective, the company expects to file an application for an emergency permit with the U.S. Food and Drug Administration shortly thereafter with other regulatory applications around the world to be filed later,” Johnson & Johnson added.
All companies that manufacture coronavirus vaccine have manufactured doses even when testing them so they can roll them out straight to people if they get FDA approval. Johnson & Johnson has contracted to supply 100 million doses to the US government if they win the EUA from the FDA.
However, the New York Times reported on Wednesday that Johnson & Johnson was behind schedule in its production.
“The pandemic shows no signs of abating, and we are all eager for more tools to help stop it. At the same time, it is too early to elaborate on the supply of our vaccine candidate, as we do not still have phase 3. data, and we have not filed or received permission for emergency use, “Johnson & Johnson said in a statement Wednesday.
“We are still in active discussions with regulators, including on the approval and validation of our production processes.”