(ORDO NEWS) — Four eminent scientists have expressed dismay about a range of vaccines designed to combat covid-19. There are concerns that they may increase susceptibility to HIV and cause AIDS, the researchers said. Science understands how great the danger is and which regions of the world will be under threat.
Some candidate vaccines for covid-19 may increase susceptibility to HIV, the team warns. Back in 2007, they found that an experimental HIV vaccine increased the risk of contracting the virus that causes AIDS for some people.
These fears have arisen at the same time as the search for a vaccine to stop the coronavirus pandemic is in full swing. Now, however, researchers are actively spreading “cautions” – in part because vaccine trials may soon begin in countries where the HIV epidemic is raging, such as South Africa.
Some vaccines, both approved and experimental, are based on various adenoviruses, which, while causing the common cold, are often harmless. The ill-fated HIV vaccine trials used an artificially engineered strain known as adenovirus serotype 5 (Ad5) to deliver the AIDS virus surface protein gene into the body. In four candidate vaccines to combat covid-19 and are currently undergoing clinical trials in several countries, including the United States, Ad5 also serves as a “vector” for the transfer of the SARS-CoV-2 virus surface protein gene, known to be cause of the current pandemic. At the same time, two of these vaccines have reached the third stage of large-scale trials in Russia and Pakistan.
In today’s issue of The Lancet, four eminent scientists are dismayed about these covid-19 vaccine candidates. They talk about their participation in a placebo-controlled trial of an AIDS vaccine called STEP. An interim STEP trial found that uncircumcised men who were naturally infected with Ad5 adenovirus prior to vaccination are particularly vulnerable to the AIDS virus.
Merck’s vaccine was the main hope: it was to crown a twenty-year search for an HIV vaccine. But the STEP test results unexpectedly caused confusion and confusion. “It took a decade to recover,” says Lancet co-author Lawrence Corey of the Center for Cancer Research. Fred Hutchinson. Lawrence Corey is now co-leader of a covid-19 network in the United States that tests vaccines for the US National Institutes of Health.
Since covid-19 vaccines based on the Ad5 adenovirus may soon appear, Lawrence Corey et al. Made a public statement that vaccines based on Ad5 could begin to be tested in groups of volunteers where HIV prevalence is high and, therefore, there is an increased risk of accidental infection during time of clinical trials. “If I were in any sub-Saharan African country and I had to make a decision to use the SARS-CoV-2 vaccine in that country, I don’t understand why I should definitely use [the vaccine] based on the Ad5 vector while there are many other alternatives, ”asks Corey.
Negative results from the STEP trials (evaluating the effectiveness of the Merck vaccine among people at high risk of HIV infection in America and Australia) also showed up in a second trial, called Phambili, when the same vaccine was tested. At the same time, it was carried out in South Africa, but was stopped early because of the results obtained after the STEP tests.
It remains unclear how Merck’s Ad5 adenovirus vaccine may have increased the risk of HIV transmission in the STEP and Phambili trials. A Lancet editorial explores several possible causes, including weakening immunity to HIV, increasing the replication of the AIDS virus, or creating more target cells for it.
In addition to the Ad5-based covid-19 vaccines, several other leading vaccines, including those developed by Johnson & Johnson and AstraZeneca in partnership with the University of Oxford, also use adenoviruses as vectors. The developers have received no evidence that any of these adenoviruses increase the risk of HIV infection.
Of all the developers of covid-19 vaccines based on Ad5, the Chinese company CanSino Biologics has advanced the farthest. In a May report published in the Lancet, the company’s scientists acknowledged the very possibility that the vector they used could increase the risk of HIV infection as “controversial” and said they would track the issue in the course of testing candidate vaccines. CanSino’s covid-19 vaccine is currently being tested for efficacy in Russia and Pakistan, both of which hope to attract more than 40,000 volunteers. CanSino is discussing starting research in Saudi Arabia, Brazil, Chile and Mexico.
China has already approved CanSino’s Ebola vaccine, which uses the Ad5 vector. CanSino CEO Yu Xuefeng said in Science that the risk of increased susceptibility to HIV can be limited with Ad5 vaccines that produce the AIDS virus protein.
“We don’t have a clear answer yet,” says Yu Xuefeng. “But if we talk about the Ebola vaccine, we have not seen anything like it.” CanSino’s Ebola vaccine has been tested in volunteers in Sierra Leone, where HIV has been relatively high, Yu Xuefeng notes. In such circumstances, the likelihood of finding a problem, if it really existed, increases.
Russian Scientific Research Institute. Gamalei created a covid-19 vaccine that uses a combination of the Ad5 and Ad26 vectors. Now in Russia, the effectiveness of this vaccine is being investigated.
Last week, ImmunityBio received approval from the US Food and Drug Administration to begin trials of a covid-19 vaccine in volunteers. This vaccine uses Ad5 as a vector. The first trial will take place in Newport Beach, California, but CEO Patrick Soon-Shiong also hopes to test the vaccine in South Africans where he grew up and studied medicine.
He calls the STEP study results “very, very fuzzy” and points out that ImmunityBio’s Ad5 contains four gene deletions that reduce the immune response it triggers. “It’s 90% off,” says Patrick Sun-Shiong.
ImmunityBio is discussing the risks with scientists and regulators in South Africa in connection with trials of a modified covid-19 vaccine based on Ad5. Volunteers who participate in the research will be informed of the potential risks, taking into account the previous results of the STEP and Phambili trials.
Sun-Shiong emphasizes that his company’s experimental covid-19 vaccine, unlike other candidate adenoviral vector vaccines, is two different SARS-CoV-2 genes and therefore may provide more protection against infection or diseases. Sun-Shiong asks: why test the vaccine only in affluent areas of Southern California? “Why not in South Africa? Why not take also low-income people from other countries of the world? ”
Pediatrician Glenda Gray, who chairs the South African Medical Research Council and participated in the Phambili trials, has had several meetings with scientists at ImmunoBio. “When [Sun-Shiong] contacted South Africa, we were very worried,” says Gray. “The Phambili test participants, very traumatized by what happened then, somehow didn’t really want a repeat in South Africa.”
However, after months of discussion, Gray continues, South Africans have concluded that regulators should consider testing (on a limited scale) the vaccine in volunteers at low risk of contracting HIV. “We decided not to throw out the baby with the water yet,” Gray said. “If this happens in South Africa, there will be a lot of discussion with the local communities because we need to make sure that the participants understand the past trials.”
South Africa appreciates the ImmunoBio initiative to start vaccine production in that country, Glenda Gray said. “South Africa’s covid-19 epidemics are in full swing, and we don’t know if we will ever get access to vaccines produced elsewhere in the world,” says Gray.
The final decision on the way forward, Gray insists, should be made by South African scientists, regulators and ethics committees. “It would be incredible arrogance to say which country is good and which science is bad,” says Gray. – Everyone knows about Phambili and STEP tests. This is why all scientists understand that you need to be careful. ”
There are no easy answers, according to Glenda Gray, who, along with Lawrence Corey and three other scientists, co-authored articles on HIV vaccines in the Lancet. “What if this vaccine is the most effective?” Asks Glenda Gray. “If it really turns out to be one of the key vaccines, we will test it one way or another.”
Contact us: [email protected]