Researchers from the Infection Biology Lab at Pompeu Fabra University and the HIV Unit at Hospital del Mar Research Institute have made a significant breakthrough in the fight against monkeypox, a zoonotic virus that causes an infectious disease similar to smallpox. Their study, published in the Journal of Medical Virology, reveals that intradermal vaccination with the JYNNEOS vaccine is the most effective way to protect individuals living with HIV from contracting the monkeypox virus.
Monkeypox is a viral infection that can spread between humans through direct contact and respiratory routes. Common symptoms include fever, headaches, muscle pain, swollen lymph nodes, rashes, respiratory and rectal symptoms, and exhaustion. While monkeypox used to appear in isolated outbreaks in Central and West Africa, a global outbreak occurred in 2022, leading to human-to-human transmission, particularly among men who have sex with men, a population group with a high prevalence of HIV.
Although there is no specific vaccine for monkeypox, the smallpox vaccine offers protection due to the antigenic similarities between the two viruses. The researchers found that the JYNNEOS vaccine, originally administered subcutaneously, was more effective when delivered intradermally. This method involves injecting the vaccine into the upper layer of the skin, where many immune cells are located. Not only does intradermal administration generate a stronger T-cell response, but it also extends the available vaccine doses by a factor of five, increasing vaccine availability without compromising efficacy.
The study also highlighted the importance of specific studies on the immune response among people with HIV, particularly those with lower levels of CD4 T-lymphocytes, which are crucial for fighting new infections. These individuals, known as immunological non-responders (INRs), control their viral loads with antiretroviral therapy but only partially recover their CD4 T-cell count. To ensure their protection against monkeypox, the researchers recommended a booster dose 28 days after the initial vaccination.
Dr. Robert Güerri, the clinician who coordinated the vaccination study in the report, emphasised the significance of these findings for immunocompromised individuals. He stated that the study supports the use of the intradermal vaccination route for those who need the vaccine the most. Dr. Andreas Meyerhans, a researcher involved in the study, added that the results provide valuable insights into preventive vaccination strategies against monkeypox in high-risk populations.
It is important to note that this study is observational and involves a small number of vaccinated individuals. Further research is needed to confirm and expand on these findings. However, the results offer a promising direction for future efforts to combat monkeypox, especially among vulnerable populations such as those living with HIV.
The researchers’ work not only sheds light on the potential of the JYNNEOS vaccine but also underscores the importance of understanding the immune response in individuals with HIV. By tailoring vaccination strategies to the specific needs of this population, we can enhance their protection against infectious diseases like monkeypox.
The study’s findings have significant implications for public health, particularly in regions affected by the monkeypox outbreak. With the intradermal administration route proving more effective and efficient in terms of vaccine availability, healthcare authorities can optimise their vaccination campaigns and prioritise the most vulnerable individuals.
