Vaccination for Monkeypox Virus Infection in Humans: A Review of Key Considerations

Abstract

Monkeypox virus infection in humans (MVIH) is currently an evolving public health concern given that >3000 MVIH cases have been reported in >50 countries globally, and the World Health Organization declared monkeypox a global health emergency on 23 July 2022. Adults (≥16 years old) usually have mild disease in contemporary studies, with a pooled case fatality rate of 0.03% (1/2941 cases). In comparison, poorer outcomes have been reported in children <16 years old (pooled case fatality rate 19% (4/21 cases)), immunocompromised patients, and pregnant women, with high rates of fetal demise in this group. Monkeypox-specific treatments include oral or intravenous tecovirimat, intravenous or topical cidofovir, oral brincidofovir, and vaccinia immunoglobulin, but the overall risk–benefit balance of monkeypox-specific treatment is unclear. Two effective vaccines exist for the prevention of MVIH: modified vaccinia Ankara and ACAM2000. Most probably, vaccination will be a key strategy for mitigating MVIH given the current rapid global spread of monkeypox, the existence of efficacious vaccines, and the uncertain risk–benefit profile of current antivirals. Priority groups for vaccination should include healthcare workers at high risk for occupational exposure, immunocompromised patients, and children. Vaccination strategies include pre-exposure vaccination, post-exposure prophylaxis, and ring vaccination of close contacts.

Monkeypox

“…The smallpox vaccine has gone through three genera_tions of medical technology but only the second and third generation vaccines are currently licensed: ACAM2000, a replication-competent smallpox vaccine, and IMVANEX (also known as JYNNEOS or IMVAMUNE; Bavarian Nordic, Hellerup, Denmark), a live, nonreplicating vaccine. 141 These can be used in two situations: pre-exposure to prevent infection and disease among those at high risk, or post exposure (ideally within 4 days of exposure) to improve infection and disease outcomes. 142…”

Monkeypox: epidemiology, pathogenesis, treatment and prevention

“…260 In the current 2022 monkeypox outbreak, it was reported that patients at least sixteen years old always have milder symptoms in the current investigations, with a pooled case fatality rate of 0.03% (1 of 2941 patients). 279 Monkeypox is more often fatal in children, which is similar to smallpox. 36,80 As of September 2022, a total of 15 deaths have been documented in this monkeypox global outbreak, in which 9 deaths in locations that have historically recorded monkeypox.…”

“…Owning to immunological cross protection among orthopoxviruses, 194,298,[394][395][396][397][398] smallpox vaccines (vaccinia virusbased) were recommended for use in the current outbreak of monkeypox. 279,[399][400][401][402][403][404][405] Epidemiological data on human monkeypox collected in Zaire from 1980 to 1984 revealed that there was a significant difference in attack rates between contacts without a vaccination scar and those who had been vaccinated in the past (7.2% vs. 0.9%). 406 Rimoin et al suggested that monkeypox incidence increased dramatically in the DRC 30 years after smallpox vaccination campaigns ended.…”

Monkeypox and Immunosuppressed Neurological Patients: What can we Advise Vaccination in Multiple Sclerosis and Neuromyelitis Optica Patients?

“…There are 2 types of vaccines: second and third generation. Second generation vaccines called replication competent vaccinia virus vaccines due to their replication capacity in mammalian cells (examples ACAM2000 and APSV approved for > 18 years old) that are associated with complications or adverse events that can be severe amongst immunocompromised individuals with no safety study in HIV population or pregnant population [5,6]. For example, after vaccination with these vaccines, we can have common local side eff ects such as pain, erythema or induration and common systemic side eff ects such as fever, chills, fatigue, myalgia, headache, nausea that are generally mild and transient [6].…”