Context
This proposal was issued at the request of the French Ministry of Health in the context of the implementation of preventive vaccination against Monkeypox among exposed groups. In its notice of June 16, 2022, the French National Authority for Health (French acronym HAS) recommended that the vaccination schedule for people targeted by this preventive vaccination should include three doses for immunocompromised people. The French HIV Society (French acronym SFLS) thus suggests a CD4 threshold below which patients living with HIV (PLHIV) should benefit from a three-dose vaccination schedule. This notice is published in an urgent context and within a short timeframe. Few scientific articles have focused on the immunogenicity of a third-generation smallpox vaccine in PLHIV, and those articles have been published by the same team [1], [2], [3]. Also, no information is currently available on the use of this vaccine before exposure to the Monkeypox virus. We therefore took into account published data and reasoned by analogy and extrapolation of knowledge on vaccine immunogenicity in PLHIV.
Literature review
The literature review showed that:
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when the CD4 count is normal, the neutralizing antibody response is identical [2] between PLHIV and non-HIV patients. When the CD4 count is lowered, the neutralizing antibody response is lower, but the difference in response is small and not significant in the medium term [3];
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the two standard doses in PLHIV with a history of AIDS are associated with the same response as the one observed in historical series of non-HIV patients, but a booster at Week 12 improves the neutralizing antibody response at Month 12 [1];
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there is no difference in side effects between PLHIV and uninfected people, including those with a history of AIDS.
SFLS proposals
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1)For PLHIV who have never been vaccinated with the first-generation smallpox vaccine, we recommend the following:
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a.A standard two-dose regimen when the CD4 count is above 200/mm3 and/or >15 % of the CD4 count (second dose at Week 4).
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b.A three-dose regimen (W0, W4, W12), when the CD4 count is lower than 200/mm3 and/or <15 % of the CD4 count.
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a.
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2)For PLHIV who have already been vaccinated with the first-generation smallpox vaccine, we recommend that the standard vaccination schedule be reduced by one dose:
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a.A one-dose regimen when the CD4 count is above 200/mm3 and/or >15 % of the CD4 count
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b.A two-dose regimen (W0, W4) when the CD4 count is lower than 200/mm3 and/or <15 % of the CD4 count
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a.
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3)
For PLHIV with a CD4 count <500/mm3 and pending further data, we recommend that the time between the first and second injection not be increased as the loss of immunogenicity may be significant.
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4)
For PLHIV with a CD4 count <50/mm3, the benefit of vaccination is unlikely because of a likely insufficient immune response. Vaccination should be considered on a case-by-case basis depending on the exposure risk.
In any case, it should be remembered that real-life efficacy of Monkeypox vaccines has to be determined more precisely for third-generation vaccines (including in PLHIV) and that a certain time ─ which is currently poorly understood ─ is necessary after vaccine administration to obtain an optimal level of protection.
Preventive vaccination cannot be the only response to the current Monkeypox virus epidemic, and must be accompanied by:
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communication on the transmission modes and on suggestive signs to exposed persons and health professionals;
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a global approach to reduce the risks of Monkeypox infection during the active period of the current epidemic, including in people who have already received the first injection: reducing the number of sexual partners, limiting exposure to body fluids, including saliva, and isolating infected people. Finally, vaccination against Monkeypox is an opportunity to check the HIV status of those vaccinated and to increase HIV prevention (screening, pre-exposure prophylaxis). These recommendations will be re-evaluated according to the results of cohort analyses of vaccinated PLHIV (preventive efficacy against Monkeypox infection, immunogenicity, etc.).
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgments
Acknowledgements
The authors thank Professors Olivier Epaulard and Odile Launay for their advice.
Ethical statement
The authors have no conflicts of interest to declare in relation to the manuscript. The work has received institutional support from the Société Française de Lutte contre le Sida.
References
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