HIV vaccine illustration. Photo: VCG

China's National Center for AIDS/STD Control and Prevention, along with other research teams, has recently completed the Phase I clinical trial of China's first replication-competent Tiantan vaccinia-based AIDS vaccine, marking a major breakthrough in the country's HIV vaccine development efforts, Beijing Daily reported on Monday.

The study innovatively used the Tiantan strain of the vaccinia virus, which was widely used as a smallpox vaccine in China. The trial confirmed the vaccine's safety and its ability to elicit effective immune responses against HIV, according to the report.

AIDS remains one of the major public health challenges facing humanity. Despite progress in antiretroviral therapy and pre-exposure prophylaxis, there are still over a million new HIV infections globally each year. 

The research team noted that the high variability of the HIV virus and its ability to attack the immune system pose significant challenges for vaccine development. Globally, over 300 HIV vaccine trials have been conducted, including 11 efficacy trials, most of which have failed to demonstrate protective immune effects.

Compared to replication-defective vectors that provide only transient antigen exposure, replication-competent viral vectors are considered a promising alternative for HIV antigen delivery. Replication-competent vectors, such as adenovirus, vaccinia virus, and cytomegalovirus, have been studied in preclinical and clinical trials. 

Against this backdrop, teams from the AIDS Prevention and Control Center under the Chinese CDC, Peking Union Medical College Hospital, and other institutions used the vaccinia virus Tiantan, previously used to eradicate smallpox, as a vector to construct a recombinant vaccine. So far, they have completed a Phase I clinical trial evaluating safety and immunogenicity in 48 healthy participants, Beijing Daily reported.

The study results confirmed the safety of the replication-competent Tiantan vaccinia-based AIDS vaccine in healthy individuals and demonstrated its ability to induce sustained HIV-specific immune responses through this enhanced immunization strategy, laying the foundation for Phase II clinical trials.

Global Times