People who get booster doses of Johnson & Johnson’s Janssen vaccine are highly protected against severe sickness and hospitalisation from the omicron type of coronavirus, according to two reports released Thursday.

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The findings suggest that the majority of COVID-19 vaccines will protect patients from the severe effects of infection, and that part of the focus on how vaccines influence immune system components known as antibodies may be misleading.

Even when the omicron form was circulating, vaccine effectiveness against hospitalisation from COVID-19 climbed to 85 percent following a booster dose of the J&J vaccine, according to a real-life study from South Africa.

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In addition, a lab research in the United States found that the vaccination generates a significant immune response from T-cells, which protect patients against severe sickness even if they don’t completely prevent the virus from infecting the body.

The company released the results of both studies in a statement, but they are still being submitted to a pre-print server and a peer-reviewed journal, according to the company.

The results of a J&J vaccine study in South Africa were examined by a team from the South African Medical Research Council. They studied the outcomes of 69,000 health-care personnel.

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“When a booster shot was administered six to nine months after a primary single dose, vaccine effectiveness increased over time from 63 percent at 0-13 days, to 84 percent at 14-27 days and 85 percent at 1-2 months post-boost,” J&J said in a statement.

“Even before you factor in the increased infectiousness of omicron, we have to remember that healthcare workers on the frontlines are at a greatly increased risk of being affected by COVID-19 in the first place,” Dr. Glenda Gray, president and CEO of the SAMRC, said in a statement.

“We are therefore encouraged to see that boosting with the Johnson & Johnson COVID-19 vaccine regimen provides strong protection in a challenging real-world setting where there is an elevated risk of exposure — not just to COVID-19, but to the highly transmissible omicron variant.”

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Separately, at the Beth Israel Deaconess Medical Center in Boston, Dr. Dan Barouch and colleagues examined blood from 65 vaccinated participants for the omicron variant. They looked at both antibodies and T-cells, which are the initial line of defence against infection.

People who received the J&J vaccination as a booster after receiving two doses of the Pfizer/BioNTech vaccine had a 41-fold rise in neutralising antibodies and a five-fold increase in CD8 killer T cells, which destroy virus-infected cells. The virus is unable to replicate and spread as a result of this. Four weeks after receiving the Pfizer vaccination, they discovered a 17-fold increase in neutralising antibodies and a 1.4-fold increase in CD8 T-cells.

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“These data are important and these data are hopeful,” Barouch told CNN. They indicate that all COVID-19 vaccines can protect people from severe disease and death, even from the omicron variant with all its mutations, he said.

“It has substantial global significance that goes well beyond J&J and goes well beyond South Africa,” he added.

The same South African team reported in the New England Journal of Medicine on Wednesday that when omicron was circulating, protection against hospitalisation from two doses of Pfizer’s vaccine dropped to around 70%, compared to 93 percent a few weeks earlier, when Delta was dominant in South Africa.

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Many research, according to Barouch, focus solely on antibodies, which can prevent the virus from invading cells at all. He said the T-cell response, which is trickier to measure, is important in providing long-term protection from severe disease.

“There’s confusion — not just in the media and the public but also among doctors and scientists — that only neutralizing antibodies equate with protection, and that’s just not true,” he said. “What we are seeing with 70% protection with Pfizer and now 85% protection with J&J — which is occurring at very low levels of neutralizing antibodies — strongly suggests T-cell responses are important in the protection that we are seeing.”

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Viruses infect cells and take over their internal machinery, transforming them into mini-virus factories. T-cells seek out and destroy infected cells, whereas antibodies bind to the exterior of viruses and prevent them from docking to cells. Although this may not fully prevent infection, it does assist to prevent the virus from spreading and causing serious sickness.

Dr. Mathai Mammen, worldwide head of research and development for Johnson & Johnson’s Janssen vaccine division, agreed. “We believe that the protection could be due to the robust T-cell responses induced by the Johnson & Johnson COVID-19 vaccine. Furthermore, these data suggest that omicron is not affecting the T-cell responses generated by our vaccine,” he said in a statement.

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The findings may also provide some comfort to the millions of people who received the Janssen vaccine. The US Centers for Disease Control and Prevention recommended the Moderna and Pfizer/BioNTech vaccines over J&J’s earlier this month, claiming that the two mRNA vaccines worked better and were safer than J&J’s, which has been linked to a rare type of blood clotting event.

mRNA vaccines use a newer method that involves messenger RNA, which is delivered into the body by lipids, which are simple fatty substances. J&J’s vaccine is an adenoviral vector vaccine, which transports genetic instructions into the body through a crippled common cold virus.

The vaccine’s design, according to J&J, is intended to trigger a strong T-cell response.