The battle against Covid-19 took a major step forward on Friday as the US moved closer to distributing its first one-shot Covid-19 vaccine, after an independent expert advisory panel recommended drug regulators authorize the Johnson & Johnson vaccine for emergency use.
The authorization would be a significant boost to the Biden administration’s vaccination plans, making Johnson & Johnson’s vaccine the third available to the public. Janssen, Johnson & Johnson’s vaccine subsidiary, told a congressional hearing this week that it expects to deliver 20m doses by March and a total of 100m doses before the end of June.
The Johnson & Johnson vaccine, along with those from Pfizer and Moderna, should provide the US with more than enough supply to vaccinate every vaccine-eligible person.
“We’re still in the midst of this deadly pandemic,” said Dr Archana Chatterjee, a voting member of the panel and an infectious disease pediatrician at Chicago Medical School, as she explained her vote in favor of recommending the vaccine. “There is a shortage of vaccines that are currently authorized, and I think authorization of this vaccine will help meet the needs at the moment.”
While regulators at the US Food and Drug Administration (FDA) do not always take the advice of their advisory panels, the agency is expected to authorize the vaccine for emergency use.
“We urgently need more vaccines [authorized] to protect the millions of Americans who remain at risk” of Covid-19 infection, said Dr Greg Poland, the editor-in-chief of the medical journal Vaccine and leader of the Vaccine Research Group at the Mayo Clinic.
“Today, we have seen clear and compelling evidence that the Janssen vaccine candidate is well tolerated, has an acceptable safety profile and most importantly is highly efficacious against Covid-19,” he said. “To me, it is clear that the known benefits vastly outweigh the known risks.”
The recommendation comes soon after the US marks 500,000 deaths from Covid-19, a toll that comes as cases decline in the US and across many countries worldwide. More than 28 million Americans have been infected by Covid-19.
“We are seeing positive trends in terms of declining cases,” said Dr Adam MacNeil, a member of the Covid-19 epidemiology taskforce with the US Centers for Disease Control and Prevention. He later added: “We are certainly not out of the woods yet.”
Importantly, Johnson & Johnson’s vaccine would also be the easiest to distribute. Unlike vaccines from Pfizer and Moderna, which require sub-zero storage, Johnson & Johnson’s vaccine can be stored at common refrigerator temperatures for up to three months. When frozen it has a shelf life of three years.
The convenience of the Johnson & Johnson vaccine comes with caveats. The company’s clinical trials were the first to show the potential impacts of Covid-19 variants, or evolutionary changes in the virus.
The vaccine was found to 85% effective at preventing severe disease and to provide complete protection against Covid-19-related hospitalization and death after 28 days. Johnson & Johnson’s vaccine was found to be 72% effective in clinical trials in the US, but only 57% effective in South Africa, where a variant called B1351 originated.
However, vaccination remains a powerful weapon, even with threats posed by variants. “Even with decreased effectiveness, vaccination may still provide partial protection against variants,” said MacNeil.
Like the Moderna vaccine, Johnson & Johnson’s product will only be available to people 18 and older. Pfizer’s vaccine is available to teenagers older than 16. Also, as with other vaccines, researchers are uncertain how long the vaccine protects against Covid-19, and whether it reduces asymptomatic transmission of the virus, although studies are promising.
Johnson & Johnson’s vaccine uses different technology from the two vaccines currently available in the US. The new vaccine uses “viral vector” technology, which introduces the body to the genetic code for the spike protein covering the outside of the coronavirus. This code is transmitted by a second, weakened virus called an adenovirus.
Immunity is provoked when the body’s immune system then recognizes the coronavirus by this key structure. Vaccines developed by Pfizer and Moderna also prompt the body to recognize spike proteins on the outside of the coronavirus, but deliver the genetic code through lipid nanoparticles, or tiny molecules of fatty acids.
Because scientists are still researching the degree to which any of the authorized vaccines prevent people from spreading Covid-19 to other people, public health authorities recommend people continue to social distance and wear masks after being vaccinated. In theory, a vaccinated person could still spread the SARS-CoV-2 virus, even if they do not experience any symptoms of the disease Covid-19.
Johnson & Johnson’s vaccines and the doses already scheduled to be delivered by Moderna and Pfizer, the makers of the two vaccines currently authorized in the US, mean there could be enough supply to vaccinate 400 million people by July. Roughly 267 million people in the US are eligible for a vaccine.
This ease of storage and one-dose regime is likely to increase pressure on the US government to pledge doses to low- and middle-income countries, which often lack the cold chain infrastructure needed to distribute the Pfizer or Moderna vaccines. Currently, dozens of low- and middle-income countries do not expect to begin broadly distributing vaccine doses until 2022.
Activists, many of whom also worked to expand access to Aids medications, have described this as “vaccine apartheid”, and a threat to the “project of global population immunity”.
Source: US Politics - theguardian.com
