Sep 2, 2021
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Another experimental HIV vaccine fell short of expectations

What’s wrong with the Johnson & Johnson vaccine

HVTN 705 is a mosaic adenovirus vector vaccine that includes protein fragments from major viral strains. The drug administration regimen assumes four vaccinations per year, and the third and fourth components include an adjuvant – an ingredient that enhances the immune response. In clinical trials Imbokodo involved about 2.6 thousand young women from five countries in southern Africa, where the female population accounts for up to 63% of new HIV cases. The participants were divided into two groups, half of them received a placebo.

The primary analysis was performed 24 months after the introduction of the first vaccine component. After assessing the level of infection in both groups, scientists found that the vaccine was only 25.2% effective. At the same time, the drug did not show any serious side effects, all women tolerated vaccination well.

These figures are significantly lower than expected, since in preclinical studies on rhesus monkeys in 2018, the HVTN 705 vaccine showed an efficacy of 67%. The developers have decided not to continue testing Imbokodo, Johnson & Johnson said in a statement.

However, hopes for an effective and safe vaccine against HIV still remain: the company is currently conducting the third phase of clinical trials of Mosaico vaccine HVTN 706, which is created using the same technology, but assumes a different composition of the drug and the schedule of administration. Research is being carried out in the Americas and Europe with the participation of homosexual and transgender men.

In early 2020, a clinical trial of an HIV vaccine was halted in South Africa. More than 5 thousand South African residents took part in it. As a result, the vaccine showed only 30% protection against the virus in those vaccinated compared to the placebo group.

For what other diseases are there still no vaccines?

Tick-borne borreliosis (Lyme disease). The infection is widespread in Siberia and western Russia. Unlike tick-borne encephalitis, borreliosis responds well to treatment, but the risk of contracting it is three times higher. Late therapy can lead to bone and joint damage. Lyme disease can also affect various organs at different stages of the disease, including the heart and brain.

In 1998, the United States approved the LYMErix recombinant Lyme disease vaccine, which, in clinical trials, has reduced the incidence rate among those vaccinated by almost 80%. But three years later, the developers voluntarily removed the vaccine from the market amid numerous statements in the media about severe side effects in those vaccinated. According to some scientists, activists of anti-vaccination organizations provoked the hype.

In 2018, there was news that another effective vaccine against Lyme disease was on its way, but there is still no data on it, and the only way to protect yourself from borreliosis is a thorough examination after a walk in the forest.

Ebola hemorrhagic fever. Native to Africa, this deadly disease is associated with severe bleeding and multiple organ failure, and those infected are unlikely to survive. Although there have been two major Ebola epidemics in Africa since 2014, and sporadic outbreaks occur almost every year, no drug has been certified for the treatment of fever. All vaccines, including those developed in Russia, have not yet gone through a full cycle of clinical trials.

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