Credit – U. Baumgarten via Getty Images – 2021 Ulrich Baumgarten
Johnson & Johnson’s Janssen Pharmaceutical Companies announced on January 29 that its unique vaccine COVID-19 is 66% effective in protecting against disease, but 85% effective in preventing serious disease – results that could make it especially valuable in the vaccinate parts of the world with weak health systems.
In comparison, vaccines already authorized in the United States – one from Moderna and one from Pfizer-BioNTech – each require two doses, with an interval of three to four weeks. Janssen’s vaccine can also be stored in normal refrigerators, unlike those of Moderna and Pfizer-BioNTech, which need to be frozen. While the vaccines from Moderna and Pfizer-BioNTech are about 94% -95% effective in protecting against COVID-19, this occurs after two doses of these injections, which are based on mRNA, a relatively new vaccine platform. Janssen’s vaccine is based on a more traditional approach: it uses a harmless human cold virus to transmit a SARS-CoV-2 gene to the human immune system, which then learns to protect the body from COVID-19. (SARS-CoV-2 is the virus that causes COVID-19.)
“A single vaccine is considered by the World Health Organization to be the best option in pandemic settings, improving access, distribution and compliance,” said J&J’s director of science, Dr. Paul Stoffels, in a statement. “The 85% effectiveness in preventing serious COVID-19 disease and preventing COVID-19-related medical interventions will potentially protect hundreds of millions of people from serious and fatal COVID-19 results.”
The J&J results came a few days after Novavax, based in Maryland, reported that, in a Phase 3 trial, its vaccine was almost 90% effective in protecting against COVID-19 disease. These results are especially encouraging, as the study was conducted among 15,000 people in the UK, where a new mutant variant of SARS-CoV-2 is rapidly gaining momentum. The high effectiveness suggests that people vaccinated with the Novavax vaccine, which is based on another proven protein injection technology made by SARS-CoV-2 to stimulate an immune response, can expect good protection against this new variant.
Dr. Paul Goepfert, director of the Alabama Vaccine Research Clinic at the University of Alabama and principal investigator of the Janssen study, says he believes that the effectiveness of the Janssen vaccine, particularly against emerging variant strains, justifies its use as quickly as possible, and potentially increasing with an additional dose if studies support such a move. Facing a rapidly changing virus requires vaccinating as many people as possible as quickly as possible, Goepfert said – sentiment echoed by the head of the National Institute of Allergy and Infectious Diseases, Dr. Anthony Fauci, during a meeting on 29 January. “Viruses cannot mutate if they cannot replicate,” said Fauci. “Therefore, we need to continue doing what we are doing, that is, intensify our ability to vaccinate as many people as possible, as quickly as possible.”
The effectiveness of the Janssen vaccine, although less than that of the Moderna and Pfizer-BioNTech versions, is probably still sufficient for authorization in most countries. Before studies on the first vaccines were completed, for example, the US Food and Drug Administration, established a minimum limit of 50-60% effectiveness for considering injections for authorization. Moderna and Pfizer-BioNTech, the first two companies to report vaccine test results, far exceeded that and set a high standard. But Goepfert says it is not a fair comparison.
“We must not just look at the [Janssen results] and say it didn’t work very well. That is not the important lesson here, ”says Goepfert. “The studies by Moderna and Pfizer were done at a time when the virus had not undergone major mutations. And you have to remember that the effectiveness of Janssen is after one dose, compared to two doses of Moderna and Pfizer. “
In the Janssen study, which involved more than 43,000 people in eight countries – the United States, Argentina, Brazil, Chile, Colombia, Mexico, Peru and South Africa – the single injection was 66% effective in protecting against moderate COVID-19 disease severe and 85% effective in specific protection against serious illnesses about a month after the injection. The effectiveness varied by country – in the USA, the study showed that the vaccine was 72% effective in protecting against moderate to severe COVID-19 disease, but 66% in Latin American countries and 57% in South Africa.
These differences may reflect the increase in different mutant strains of SARS-CoV-2 worldwide. In the study, most cases of the disease in South Africa, for example, were caused by the mutant virus, which, according to scientists, shows signs of becoming resistant to vaccines already authorized. The Janssen vaccine targets the spike protein that SARS-CoV-2 uses to bind and infect human cells, and the variant that circulates in South Africa has changed its genetic structure so that it binds in a slightly different way. This means that immune defenses, such as antibodies that are generated by vaccines and designed to block the original spike protein, may not be as effective in blocking the variant.
Still, Janssen’s study shows that vaccine-induced immunity was sufficient to protect against COVID-19 and, perhaps more importantly, protect against death after infection. The study was conducted in collaboration with scientists from NIAID and the United States Department of Health and Human Services Advanced Biomedical Research and Development Authority, and will continue to follow participants for two years. Goepfert says the company is also studying a two-dose regimen to see if it can further increase immune protection.
Testing already authorized COVID-19 vaccines, as well as future vaccines, against emerging mutations will be a priority for scientists and regulators. So far, Moderna, Pfizer-BioNTech and Novavax have reported that tests on blood collected from people vaccinated with their vaccines show that they are able to neutralize variants in the UK and South Africa, although Moderna and Novavax have discovered that the recipients produced less antibodies against South African tension. Still, all studies show that the immune response generated by vaccines remains strong enough to protect against disease.
Keeping up with new virus mutations is a priority for the US Centers for Disease Control and Prevention, said agency director Dr. Rochelle Walensky during the January 29 briefing. CDC is expanding its viral sequencing efforts by working with government, academic and commercial partners to collect more samples from patients with COVID-19 and genetically sequence the virus they contain, to monitor changes in viral genomes that may signal impending resistance to vaccines or drugs. “We are asking for surveillance from all states, about 750 samples per week and, with the collaboration of the university, we hope to do this thousands per week,” she said.
Janssen plans to submit an application for emergency use authorization in the U.S. and elsewhere. If authorized, it will be up to global health leaders to decide whether the convenience of administering the single dose, and its ability to be stored in refrigerated conditions, is sufficient to justify the lower overall effectiveness of the Janssen injection.