Logo of Phnom Penh Post newspaper Phnom Penh Post - J&J booster trims severe Omicron cases, study finds



J&J booster trims severe Omicron cases, study finds

Content image - Phnom Penh Post
The Johnson & Johnson (J&J) Covid vaccine. AFP

J&J booster trims severe Omicron cases, study finds

A preliminary South African government study published on December 30 showed a booster of the Johnson & Johnson (J&J) Covid vaccine was 85 per cent effective in preventing hospitalisation from the Omicron variant, a finding that helps revive the shot’s reputation.

The South African Medical Research Council compared 69,000 health care workers who received two doses of the vaccine, based on viral vector technology, against a group of people who were unvaccinated.

The research, which has not yet been peer reviewed, was conducted from November 15 to December 20, a time when the heavily-mutated Omicron variant increased from 82 to 98 per cent of Covid-19 cases in the country.

When a booster shot was given six to nine months after the first dose, vaccine efficacy against hospitalisation increased over time, from 63 per cent at 0-13 days to 85 per cent one to two months post-boost.

“This data is important given the increased reliance on the Ad26.COV.2 vaccine in Africa,” wrote the authors, using the formal name for the J&J shot.

The result was also hailed by the company. In a statement, J&J scientist Mathai Mammen said it showed the vaccine “remains strong and stable over time, including against circulating variants such as Omicron and Delta”.

Around half a million South African health staff have received Johnson jabs as part of clinical trials.

Africa’s hardest-hit country, South Africa has recorded more than 3.4 million cases and 90,000 deaths since the start of the pandemic.

An earlier South African study in December found that two doses of the Pfizer-BioNTech vaccine prevented hospital admissions by up to 70 per cent. Results for three doses of that vaccine aren’t yet known.

The news comes weeks after the US formally recommended mRNA vaccines, made by Pfizer and Moderna, over the J&J shot, because of greater risks related to a rare form of blood clotting.

Preliminary lab studies had also shown that the J&J vaccine triggers fewer neutralising antibodies – Y-shaped proteins that block infection – against the heavily mutated Omicron variant, compared to mRNA vaccines, and it was suggested that it would be less effective in real life too.

The reason it performs better in the real world than some expected could be it evokes a heightened response of another part of the immune system, known as cellular immunity.

A separate, small analysis carried out by the Beth Israel Deaconess Medical Center in the northeastern US city of Boston on 65 individuals found that a J&J booster on top of two doses of the Pfizer Covid vaccine might provide greater protection than three doses of the Pfizer vaccine.

Though antibody levels surged to high levels after three doses of Pfizer, they also waned within a few weeks, while they rose steadily after two Pfizer shots and a J&J shot, and were at higher levels after four weeks.

Boosting with the J&J vaccine also elicited a strong increase in “killer T cells”.

Though they can’t stop infection, killer T cells search for cells that have been infected with the virus and destroy them, helping prevent severe illness. They are able to withstand variants far better than antibodies.

Overall, the data might mean that mix-and-match boosting could provide stronger protection than continuing with the same vaccine, but the long-term durability of both strategies needs further study, said J&J.

MOST VIEWED

  • Hong Kong firm done buying Coke Cambodia

    Swire Coca-Cola Ltd, a wholly-owned subsidiary of Hong Kong-listed Swire Pacific Ltd, on November 25 announced that it had completed the acquisition of The Coca-Cola Co’s bottling business in Cambodia, as part of its ambitions to expand into the Southeast Asian market. Swire Coca-Cola affirmed

  • Cambodia's Bokator now officially in World Heritage List

    UNESCO has officially inscribed Cambodia’s “Kun Lbokator”, commonly known as Bokator, on the World Heritage List, according to Minister of Culture and Fine Arts Phoeurng Sackona in her brief report to Prime Minister Hun Sen on the night of November 29. Her report, which was

  • NagaWorld union leader arrested at airport after Australia trip

    Chhim Sithar, head of the Labour Rights Supported Union of Khmer Employees at NagaWorld integrated casino resort, was arrested on November 26 at Phnom Penh International Airport and placed in pre-trial detention after returning from a 12-day trip to Australia. Phnom Penh Municipal Court Investigating Judge

  • Sub-Decree approves $30M for mine clearance

    The Cambodian government established the ‘Mine-Free Cambodia 2025 Foundation’, and released an initial budget of $30 million. Based on the progress of the foundation in 2023, 2024 and 2025, more funds will be added from the national budget and other sources. In a sub-decree signed by Prime Minister Hun Sen

  • Two senior GDP officials defect to CPP

    Two senior officials of the Grassroots Democratic Party (GDP) have asked to join the Cambodian People’s Party (CPP), after apparently failing to forge a political alliance in the run-up to the 2023 general election. Yang Saing Koma, chairman of the GDP board, and Lek Sothear,

  • 11th Chaktomuk Short Film Festival draws to close

    Cambodia's 11th Chaktomuk Short Film Festival wrapped up successfully on November 28 after a four-day run, with the film “Voice of the Night” awarded top prize for 2022. Sum Sithen, the organiser of the short film festival, told The Post that the number of attendees to the