Technician preparing a dose of Johnson & Johnson’s COVID-19 vaccine for use in a clinical trial.Credit: Michael Ciaglo / Getty
Another vaccine has been shown to protect against COVID-19 – and this time with just a single dose.
On January 29, pharmaceutical giant Johnson and Johnson (J&J) of New Brunswick, New Jersey, announced that its vaccine was 66% effective overall in protecting against moderate to severe COVID-19, 28 days after a single injection. The vaccine was tested in a phase III study involving almost 44,000 participants in the United States, Latin America and South Africa.
An effective single dose vaccine would be a welcome boost to efforts to contain the pandemic – it would offer faster protection than most vaccines approved for use so far, which are given in two injections weeks apart.
But while the vaccine was 72% effective in the United States, it was only 57% effective in South Africa, where a variant of the virus that can prevent some immune responses is spreading. The vaccine was 66% effective in Latin American countries, including Brazil, where other worrying variants were discovered.
These data echo the findings announced by Novavax, a company in Gaithersburg, Maryland, which reported that its coronavirus vaccine was less effective in a trial conducted in South Africa than in the UK arm.
These vaccine studies illustrate the implications of emerging variants of the coronavirus, said Anthony Fauci, director of the United States National Institute of Allergy and Infectious Diseases in Bethesda, Maryland. “Now we have the clinical consequence of the real world and we can see that we will be challenged,” he told reporters at a news conference. “It is really a wake-up call for us to be agile and adjust as this virus will certainly continue to evolve.”
Encouraging results
Although the J&J vaccine was less effective in South Africa, protection specifically against severe COVID-19 remained stable at 85% in all geographic regions studied, said Mathai Mammen, global head of Janssen Research and Development, a subsidiary of J&J. The company plans to conduct further studies to assess the effect of the variants on effectiveness, he said, and to examine the impact of the vaccine on disease transmission.
The overall effectiveness of the vaccine is well below some other coronavirus vaccines: the vaccines produced by Moderna in Cambridge, Massachusetts and Pfizer in New York City were both about 95% effective. But the results are still encouraging, says Stephen Griffin, a virologist at the University of Leeds, UK. “As with any vaccine, it is about how you implant it,” he says.
J&J will apply to the United States Food and Drug Administration for an emergency use authorization within the next few days and then request other regulators, including the European Medicines Agency.
A new source of vaccines is to be welcomed: despite a steady stream of promising results since last November, limited supplies and rising coronavirus infections have left many countries with additional vaccines to burst the market. J&J plans to produce one billion doses of its vaccine by the end of the year.
Easier logistics
Most other authorized COVID vaccines rely on two injections to provide protection: an initial dose followed, a few weeks later, by a “boost” to stimulate the immune system’s memory cells. The result is a powerful immune response, but the need for two doses halves the number of people who can be vaccinated with existing supplies.
And bringing vaccinees back to their second dose can be a logistical challenge, especially with people who have nowhere to live, use substances or live in rural areas, says Krutika Kuppalli, an infectious disease specialist at the Medical University of South Carolina in Charleston. . “The J&J vaccine offers a potentially easier set of logistics,” she says, “particularly for certain patient populations that are difficult to reach”.
The vaccine works similarly to that produced by AstraZeneca of Cambridge, UK, and the University of Oxford, UK – it uses a harmless virus to transport the genetic code for a coronavirus protein called pico in human cells. This means that the J&J vaccine can be stored in normal refrigerators, making it much easier to work with than the RNA vaccines produced by Pfizer and Moderna. The Pfizer vaccine, for example, should be stored at very low temperatures and will only remain stable at room temperature for a short period of time. “You have to be very precise when calculating who is going to vaccinate,” says Kuppalli. “After defrosting the vaccine, you only have six hours to give it.”
These logistical obstacles have contributed to delay the vaccine’s implantation in some countries, while others still struggle to obtain sufficient doses. J&J pledged to supply its non-profit vaccine during the pandemic and, in December, the company signed a principle agreement to supply hundreds of millions of doses to COVAX, an effort to distribute vaccines to lower countries’ income.
J&J is conducting a separate study to test the effectiveness of a two-dose regimen for its vaccine.