Omicron-like variants could be stifled by AIDS treatment programs: report

Omicron has caused worldwide alarm as it appears to be more transmissible than previous strains.

South Africa should increase the supply of antiretroviral drugs to millions of people infected with HIV to potentially reduce the risk of new variants of Covid-19 emerging, scientists have said.

In a revised study of a person with HIV with limited adherence to antiretroviral therapy or an ART program, scientists led by Alex Sigal of the Africa Health Research Institute in Durban, South Africa, analyzed the mutations that developed when the female subject harbored the Covid-19 virus for 216 days. HIV, advanced cancer, and some other diseases suppress the immune system, allowing other infections to take hold. ART treatment restores the body’s ability to fight infections.

“Characterizing the evolution of SARS-COV-2 in specific geographic areas can help predict the properties of variants originating from those regions,” Sigal said in the revised preprint, which was submitted Tuesday. “If immunosuppression by advanced HIV drives the progression of SARS-COV-2, ART coverage should be increased to prevent it.”

While South Africa has the largest ART program in the world, it also has 8.2 million people infected with the disease. Many of its neighbors have high HIV prevalence rates. While the majority of patients in Africa’s most industrialized country are on treatment, several million are not. The pandemic has further disrupted programs.

The theory that omicron developed in an immunocompromised person is only a hypothesis. Others include that the coronavirus jumped back into an animal, mutated and then infected a human. Another possibility is that he quietly moved to an area with little surveillance and poor access to healthcare and was later found in South Africa, where the sequencing of Covid-19 samples is relatively high.

The new variation that developed in the South African subject began as an infection with the original viral strain, first identified in Wuhan, China.

Cultures of isolated virus were taken on day 6, day 20 and day 190 – called D6, D20 and D190 – after infection. The sample propagated from day 190 eluded antibodies produced from previous infections or vaccinations to a level similar to the beta variant. Samples from days 6 and 20 did not escape antibodies.

The D190 virus had a “pronounced” ability to evade antibodies produced in response to infection with delta, the variant that has swept the world this year causing severe illness and death.

“The driving force behind the evolution of D190 may have been the presence of very low levels of antibodies against SARS-COV-2, which can select for antibody escape mutations,” the scientists said.

The researchers warned that only one subject out of 93 HIV-infected people in the study showed strong progression of the coronavirus. Still, that could mean around 80,000 people in South Africa could be susceptible to harboring Covid-19 for long periods of time, allowing it to mutate, they said.

The potential for change from Covid-19 is not specific to infecting someone with HIV, but to infecting anyone with a weakened immune system with the coronavirus, Sigal said by text message.

The South African subject was largely asymptomatic throughout his infection, the scientists said.

One explanation for the lack of symptoms could be that the virus “had low pathogenicity to begin with”, they said. “The omicron variant emerged while this work was being reviewed and has mutations at many of the same sites as the evolving virus” that was the subject of the study, the scientists said.

A separate study published this week by scientists led by Sigal showed that the Covid-19 vaccine produced by Pfizer Inc. and BioNTech SE was less effective against omicron than previous variants.

If the “strain described in this work and omicron share a common evolutionary mechanism, omicron may have beta-like serology, substantial but incomplete escape of neutralizing immunity induced by mRNA vaccines, and strong escape of induced immunity by the delta, which can lead to reinfections,” the scientists said in the preprint. “Whether other characteristics might also be shared, such as potentially mild pathogenicity, is still unknown.”

Omicron has caused worldwide alarm as it appears to be more transmissible than previous strains. Still, early evidence from hospitals indicates it may be less pathogenic, meaning it could cause less severe illness.

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