Data from clinical trials with two covid-19 vaccines show that a coronavirus variant first identified in South Africa is reducing its ability to protect against the disease, highlighting the need to vaccinate large numbers of people as soon as possible , scientists said.
Vaccines from Novavax and yes Johnson & Johnson were hailed as important future weapons in reducing deaths and hospitalizations in a pandemic that infected more than 101 million people and killed more than 2 million worldwide.
But they were significantly less effective in preventing covid-19 in study participants in South Africa, where the new potent variant is widespread, compared to countries where this mutation is still rare, according to preliminary data released by the companies.
“Clearly, the mutations have a diminishing effect on vaccine effectiveness,” said Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases, in an interview. “We can see that we will be challenged.”
Novavax reported intermediate trial results on Thursday (28) that showed that its vaccine was 50% effective in preventing covid-19 among people in South Africa.
This compared to the UK’s advanced stage results, where the vaccine was up to 89.3% effective in preventing the disease.
On Friday, J&J said a single injection of its coronavirus vaccine was 66% effective in a massive trial on three continents.
But there were big differences by region. In the United States, where the South African variant was first reported this week, effectiveness reached 72%, compared to only 57% in South Africa, where the new variant, known as B 1,351, accounted for 95% of cases of covid-19 recorded in the study.
The other highly transmissible variant first discovered in the UK and now in more than half of the US states has been less able to escape the vaccine’s effectiveness than its South African counterpart.
The new findings, however, raise questions about how the highly effective vaccines in Pfizer with the partner BioNTech and Modern will come out against new variants. The two vaccines showed about 95% effectiveness in tests conducted mainly in the United States before new versions of the virus were identified in other countries.
“It’s a different pandemic now,” said Dan Barouch, a researcher at Beth Israel Deaconess Medical Center at Harvard University Medical Center in Boston, who helped develop the J&J vaccine.
Barouch said there are now a wide variety of new variants circulating, including in Brazil, South Africa and even the United States, which are substantially resistant to antibodies induced by the vaccine.
Pfizer’s chief executive, Albert Bourla, said there is “a great possibility” that emerging variants could render the company’s vaccine ineffective.
“It is not yet the case … but I think it is very likely that it will happen one day,” said Bourla at the World Economic Forum. The drugmaker is considering whether its vaccine needs to be changed to defend itself against the South African variant.
Ability to reduce hospitalizations
Experts said all four vaccines are still of great value in their ability to reduce severe cases of covid-19.
” The final game is to prevent death, to prevent hospitals from going into crisis – and all of these vaccines, even against the South African variant, seem to do so substantially,” said Amesh Adalja, an infectious disease specialist at the Johns Hopkins Center for Health Security.
For example, the J&J vaccine was 89% effective in preventing serious diseases in South Africa.
J&J scientific director Paul Stoffels said he suspected that a type of immune system reaction called the T cell response is playing a protective role and may be helping to prevent serious illnesses.
“We knew this to some extent, but it is also better and very confirming that we can see it now at the clinic,” said Stoffels in an interview.
However, Fauci said the diminished efficacy rates underscore the need to follow variants closely and to speed up vaccination efforts before new and even more dangerous mutations emerge.
“ The best way to prevent a virus from evolving is to prevent it from replicating. […] And you do that by vaccinating people as soon as possible. “
Copyright © Thomson Reuters.