The U.S. is one step closer to providing another Covid-19 vaccine after a group of experts unanimously decided on Friday to recommend emergency approval for a shot developed by Johnson & Johnson.
The independent panel, which consisted mostly of doctors, voted 22-0 in support of the vaccine, without anyone abstaining. These votes are not binding on the FDA, but the agency often follows the recommendations of its panels. A decision could be made this weekend. The two Covid vaccines currently approved for emergency use received their approval the day after the respective meetings of the advisory body.
The Johnson & Johnson vaccine would provide an alternative to those currently available from the Pfizer and BioNtech alliances, as well as Moderna. These messenger RNA vaccines must be distributed and stored in extremely cold temperatures and then thawed before use. These recordings are given in two doses, weeks apart. The J&J vaccine can be stored at refrigerator temperatures. Another key difference is that the J&J burst requires a single shot. Together, these features will make it easier for the J&J vaccine to be distributed to more people in more locations through existing distribution channels.
The panel members were in favor of the J&J vaccine, saying the safety and efficacy data supported its approval. However, panellists also cautioned the public against picking vaccine favorites.
“It’s important that people don’t believe that one vaccine is better than another,” said Cody Meissner, an infectious disease expert and professor of pediatrics at Tufts University School of Medicine. “There is no preference for one vaccine over another, and all vaccines seem to operate with what appears to be the same safety and effectiveness as they do today.”
An emergency authorization is not the same as a permit. Federal law allows the FDA to market unapproved medical devices for emergency situations such as a pandemic. Permissions are only valid for the duration of the emergency. These permissions can also be revoked if new data shows that the product is not safe or effective. Stanley Perlman, a professor in the departments of microbiology and immunology at the University of Iowa, said that while clinical studies to date have provided data on the vaccine’s safety and effectiveness, “it would be nice to have more.”
The J&J vaccine is new, but compared to the mRNA vaccines, the technology behind it has a slightly longer track record. The J&J vaccine uses AdVac technology, the same platform used to make the company’s Ebola vaccine, which the FDA approved in 2019. The technology takes the virus that causes colds and modifies it so that it doesn’t cause disease. This manipulated virus is the transport vehicle that transports a section of the genetic code for the spike protein of the novel coronavirus into the cells. The genetic material serves as a blueprint from which the body’s cells produce spike proteins. The immune system responds by producing antibodies against these proteins and conferring immunity.
The clinical data to date for the J&J Covid vaccine includes 44,000 adults from around the world. In the Phase 3 data reported in late January, the vaccine was 66% overall effective in preventing moderate to severe infections 28 days after vaccination. In addition, the vaccine showed 85% effectiveness in preventing serious illnesses and showed complete protection against hospitalizations and deaths related to Covid, also measured on day 28.
These markings appear to be inferior to more than 90% efficacy demonstrated in mRNA vaccine trials. However, cross-experiment comparisons are difficult and can be misleading because experiments have different designs and goals. In addition, the mRNA studies were performed at the beginning of the year, when fewer variants were in circulation. Public health experts have stated that if these vaccines were tested under current conditions, their rates of effectiveness could also be lower.
Plans are underway to collect more data on J & J’s shot, including a study of the vaccine in children and adolescents. Johan Van Hoof, Global Head of Infectious Diseases and Vaccines at J & J’s Janssen subsidiary, told the Advisory Board that a clinical trial is expected to begin in the spring to test the vaccine in 17 year olds and younger . He also said the company is looking into how the vaccine will respond to variants of the novel coronavirus.
Shortly after the Friday meeting, the FDA issued a statement that it would “work quickly” with J&J to clear and grant emergency clearance. The agency added that it had informed federal partners involved in vaccine allocation and distribution so that they would be ready.
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