single-dose Covid-19 vaccine worked safely and should be authorized for use in the U.S., a panel of experts advised federal health regulators Friday.
The advisory committee’s vote in support of the vaccine’s authorization is the last step before the U.S. Food and Drug Administration issues a decision, which is expected Saturday.
The panel, a group of 22 medical specialists in fields like internal medicine, pediatrics, vaccines and epidemiology, regularly advises the FDA about experimental vaccines. It voted to recommend shots from
Pfizer Inc.
and partner
SE and
Moderna Inc.
before the agency authorized them in December.
During the all-day public meeting, representatives from the FDA and J&J discussed the safety and effectiveness of the company’s vaccine in a 44,000-plus subject study, as well as how effective the J&J vaccine is in preventing new cases caused by variants.
The give-and-take of questions and answers can be valuable in bolstering public confidence in the shot, according to FDA officials.
The vaccine was 66% effective at protecting people from moderate to severe Covid-19, an FDA review found, and even more effective at preventing severe disease alone.
“If authorized, Janssen’s vaccine candidate would play a pivotal role in the global effort to fight Covid-19,”
Johan Van Hoof,
global head of vaccines research at J&J’s Janssen pharmaceutical unit, said during the panel’s meeting. “A single-dose regimen offers the ability to vaccinate a population faster.”
A rollout of the J&J vaccine could add enough shots in the U.S. by the end of March to boost the total number of people vaccinated by 20%. Health authorities are pushing to inoculate enough people as quickly as possible so that business, schools and other establishments can fully reopen.
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J&J has said it would deliver about 20 million doses for U.S. use by the end of March.
The FDA often convenes public meetings of outside experts to scrutinize experimental drugs, devices and vaccines up for agency approval, in part to boost public acceptance of the products should they be cleared for wide use.
J&J’s vaccine appeared to be safe in its pivotal study, the FDA found, aside from being effective.
“The known and potential benefits of Ad26 outweigh the known and potential risks,” Macaya Douoguih, head of clinical development and medical affairs at J&J’s Janssen unit, said during Friday’s meeting, using a code name for J&J’s vaccine.
FDA medical officer Yosefa Hefter said there are still unknowns about the vaccine, including the duration of immune protection and the safety and effectiveness in children.
An FDA analysis for the committee meeting also said rare cases of deep vein clots and of blockages in lung arteries were slightly more common in vaccine recipients than in placebo patients, and that the FDA considers these as “of clinical interest.”
The vaccine was effective “across demographic subgroups,” the FDA said. The demographic subgroups in the large study of J&J’s vaccines included racial and ethnic groups such as Black, Latino and Asian people, and age groups such as those 60 years and older.
Researchers also assessed efficacy in people who had underlying medical conditions including obesity and high blood pressure before entering the clinical trial. Sometimes vaccines don’t work as well in older people because of weakened immune systems.
One exception was that the vaccine appeared to be less effective in people 60 and older who had certain underlying medical conditions like diabetes and high blood pressure.
The Pfizer-BioNTech and Moderna vaccines also worked effectively across various demographic subgroups.
The vaccine was less effective in South Africa, where a more-transmissible Covid-19 variant has thrived, than in the U.S. J&J is among the companies working on new shots targeting the new strain, against which several current vaccines don’t appear to work as well.
J&J’s Covid-19 shot was, however, very effective against severe and critical cases in South Africa. The vaccine was 73.1% effective in preventing such cases occurring at least 14 days after vaccination, and 81.7% effective in preventing such cases at least 28 days after vaccination.
How Viral Vector Vaccines Work
Johnson & Johnson’s vaccine relies on a different mechanism for conferring immunity than traditional vaccines.
Traditional Vaccines
1. In classic vaccines, such as those against measles and polio, the patient is inoculated with weakened or inactivated versions of the virus. This triggers the immune system to produce specialized antibodies that are adapted to recognize the virus.
2. After vaccination, the antibodies remain in the body. If the patient later becomes infected with the actual virus, the antibodies can identify and help neutralize it.
Johnson & Johnson’s Vaccine
Scientists have isolated the genes in coronavirus responsible for producing these spike proteins. The genes are spliced into weakened, harmless versions of other viruses.
Instead of using the whole virus to generate an immune response, these vaccines use only coronavirus’s outer spike proteins, which are what antibodies use to recognize the virus.
Weakened virus with
spike protein genes
When injected into a patient, the genetically engineered viruses enter healthy cells where they produce coronavirus spike proteins.
The spike proteins produced by the cells prompt the immune system to mount a defense, just as with traditional vaccines.
Vaccine-generated antibody response
1. In classic vaccines, such as those against measles and polio, the patient is inoculated with weakened or inactivated versions of the virus. This triggers the immune system to produce specialized antibodies that are adapted to recognize the virus.
2. After vaccination, the antibodies remain in the body. If the patient later becomes infected with the actual virus, the antibodies can identify and help neutralize it.
Johnson & Johnson’s Vaccine
Scientists have isolated the genes in coronavirus responsible for producing these spike proteins. The genes are spliced into weakened, harmless versions of other viruses.
Instead of using the whole virus to generate an immune response, these vaccines use only coronavirus’s outer spike proteins, which are what antibodies use to recognize the virus.
Weakened virus with
spike protein genes
When injected into a patient, the genetically engineered viruses enter healthy cells where they produce coronavirus spike proteins.
The spike proteins produced by the cells prompt the immune system to mount a defense, just as with traditional vaccines.
Vaccine-generated antibody response
1. In classic vaccines, such as those against measles and polio, the patient is inoculated with weakened or inactivated versions of the virus. This triggers the immune system to produce specialized antibodies that are adapted to recognize the virus.
2. After vaccination, the antibodies remain in the body. If the patient later becomes infected with the actual virus, the antibodies can identify and help neutralize it.
Johnson & Johnson’s Vaccine
Scientists have isolated the genes in coronavirus responsible for producing these spike proteins. The genes are spliced into weakened, harmless versions of other viruses.
Instead of using the whole virus to generate an immune response, these vaccines use only coronavirus’s outer spike proteins, which are what antibodies use to recognize the virus.
Weakened virus with
spike protein genes
When injected into a patient, the genetically engineered viruses enter healthy cells where they produce coronavirus spike proteins.
The spike proteins produced by the cells prompt the immune system to mount a defense, just as with traditional vaccines.
Vaccine-generated antibody response
1. In classic vaccines, such as those against measles and polio, the patient is inoculated with weakened or inactivated versions of the virus. This triggers the immune system to produce specialized antibodies that are adapted to recognize the virus.
2. After vaccination, the antibodies remain in the body. If the patient later becomes infected with the actual virus, the antibodies can identify and help neutralize it.
Johnson & Johnson’s Vaccine
Instead of using the whole virus to generate an immune response, these vaccines use only coronavirus’s outer spike proteins, which are what antibodies use to recognize the virus.
Scientists have isolated the genes in coronavirus responsible for producing these
spike proteins. The genes are spliced into weakened, harmless versions of other viruses.
Weakened virus with
spike protein genes
When injected into a patient, the genetically engineered viruses enter healthy cells where they produce coronavirus spike proteins.
The spike proteins produced by the cells prompt the immune system to mount a defense, just as with traditional vaccines.
Vaccine-generated antibody response
J&J, citing preliminary evidence in an analysis released by the FDA, said the vaccine was 65.5% effective in preventing asymptomatic infections in a subset of study subjects.
Health authorities have been watching whether Covid-19 shots can stop people without symptoms from transmitting the virus. The virus has largely been spread by people who were infected but didn’t realize it because they had no symptoms.
The vaccine was less effective in South Africa, where a more-transmissible Covid-19 variant has thrived, than in the U.S. J&J is among the companies working on new shots targeting the new strain, which several current vaccines don’t appear to work as well against.
Write to Thomas M. Burton at [email protected] and Peter Loftus at [email protected]
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