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Promising results from first vaccines tested against COVID-19 variant in South Africa

Interim results show that Johnson & Johnson’s one-dose vaccine was 85% effective in preventing severe Covid-19 no matter what the variant.

Photo credit: Biovac Institute

Covid-19 vaccines made by pharmaceutical firms Novovax and Johnson & Johnson (J&J) have been shown to reduce the risk of moderate to severe COVID-19 by about 60% in people infected with the new variant, the companies announced this week. 

Preliminary data from a late-stage clinical trial shows that J&J’s one-dose jab reduced the risk of moderate to serious Covid-19 by about 57% in South African participants. 

Novovax reduced this risk by 60% in HIV-negative people, which made up the majority of people in the study. But in a small group of people living with HIV in the Novavax phase study, the jab did not work as well — bringing the vaccine’s overall efficacy down to 49.4%. 

Still, lead researcher on the South African Novavax trial and executive director of the Vaccines and Infectious Diseases Analytics Research Unit (VIDA) at Wits University Shabir Madhi is cautious about interpreting the findings from such a small sample of people living with HIV.

Because the number of HIV-positive people included in the study was so small, Madhi explained, even a single case of Covid-19 in this group would statistically affect how well the jab would be shown to work.

“I think we should just avoid reading anything into the results among HIV-positive people,” Madhi warned. “[Those results] were among 240 individuals and [in a sample so small] even one case in either direction can [change] that efficacy estimate.”

J&J’s one-shot wonder

The firms’ announcements, issued through press releases, came less than 24 hours apart. The findings have not yet been peer-reviewed. Although both vaccines performed more poorly against the Covid-19 variant originally discovered in South Africa than in other variants, both vaccines show promise in reducing the risk of deadly Covid-19 cases from the variant, researchers say. 

Interim analysis from J&J’s late-stage vaccine trial showed it to be 85% effective in preventing severe disease regardless of what Covid-19 variant was behind the infection. In a press release, the firm also said the one-dose jab provided complete protection against Covid-19 hospitalisations or deaths during the first month after people received the jab. 

“A one-shot vaccine is considered by the World Health Organisation to be the best option in pandemic settings,” J&J Vice Chairman of the Executive Committee and Chief Scientific Officer  

Paul Stoffels said in a statement. “[An] 85% efficacy in preventing severe Covid-19 disease and … [death] will potentially protect hundreds of millions of people.”

He continued: “It also offers the hope of helping ease the huge burden placed on healthcare systems and communities.”

We’re seeing a trend

The earlier-phase trial of Novovax’s two-dose jab was not designed to measure how well it protected against hospitalisations considering its smaller size and younger sample, Madhi explains. Still, he believes that the inoculation will ultimately reduce hospitalisations. 

“The trend we’re seeing with all of the vaccines that have reported results and shown efficacy have shown higher efficacy for more severe disease,” Madhi told The Continent. “I believe this vaccine will have an impact on hospitalisation and will have an impact on [reducing] severe disease by probably [more] than 60%.”

Participants in the J&J trial will be followed up for two years so the firm says data on the vaccine may be updated. Those in the Novovax trial will also be followed up and the firm has already embarked on an important late-stage clinical trial to provide additional data on how well the vaccine works.

J&J’s vaccine is currently under review for regulatory approval in South Africa, which would be the first step in allowing the vaccine to be used in the country. J&J vaccines will also form part of the roughly 670-million Covid-19 vaccine doses secured for the continent by the African Union.

This story was first published on 30 January 2021 in The Continent magazine.