Estimation of anti-orthopoxvirus immunity in Moscow residents and potential risks of spreading Monkeypox virus

Abstract

WHO has declared the outbreak of monkeypox as a public health emergency of international concern. In less than three months, monkeypox was detected in more than 30 000 people and spread to more than 80 countries around the world. It is believed that the immunity formed to smallpox vaccine can protect from monkeypox infection with high efficiency. The widespread use of Vaccinia virus has not been carried out since the 1980s, which raises the question of the level of residual immunity among the population and the identification of groups requiring priority vaccination. We conducted a cross-sectional serological study of remaining immunity among Moscow residents. To do this, a collection of blood serum samples of age group over 30 years old was formed, an in-house ELISA test system was developed, and a virus neutralization protocol was set up. Serum samples were examined for the presence of IgG antibodies against Vaccinia virus (n=2908), as well as for the ability to neutralize plaque formation with a Vaccinia virus MNIIVP-10 strain (n=299). The results indicate the presence of neutralizing antibody titer of 1/20 or more in 33.3 to 53.2% of people older than 45 years. Among people 30-45 years old who probably have not been vaccinated, the proportion with virus neutralizing antibodies ranged from 3.2 to 6.7%. Despite the higher level of antibodies in age group older than 66 years, the proportion of positive samples in this group was slightly lower than in people aged 46-65 years. The results indicate the priority of vaccination in groups younger than 45, and possibly older than 66 years to ensure the protection of the population in case of spread of monkeypox among Moscow residents. The herd immunity level needed to stop the circulation of the virus should be at least 50.25 – 65.28%.

Study of Viral Coinfection of the Ixodes persulcatus Ticks Feeding on Humans in a Natural Focus of the South of the Far East

“…In epidemiological and epizootological terms, this property of the new virus is a potentially dangerous and naturally causes concern. Moreover, in recent years, natural populations of various representatives of the smallpox virus have become more active in the world [ 30 , 31 , 32 ]. We admit the possibility of expanding the ecological and virological competencies of ticks containing pathogens such as the Kiparis-144 virus.…”

Systematic Review on the Efficacy, Effectiveness, Safety, and Immunogenicity of Monkeypox Vaccine

“…Table 1 shows the characteristics of the included studies. One study was conducted across countries [34]; one study across Europe [35]; twenty studies in USA [26,33,[36][37][38][39][40][41][42][43][44][45][46][47][48][49]; four studies in Democratic Republic of the Congo (DRC) [50][51][52][53]; two studies in Israel [54,55], Netherlands [56,57], United Kingdom (UK) [58,59], and France [60,61]; one study in Congo [62], China [63], Italy [64], Germany [65], Russia [66], Australia [67], and Spain [68]. All studies except three [57,69,70] were peer-reviewed.…”

“…Of note, the production of antibodies differed across ages: NAbs titer of 1/20 or more in 33.3 to 53.2% of people older than 45 years. Among people 30-45 years old who probably have not been vaccinated, the proportion with virus NAbs ranged between 3.2 and 6.7% [66].…”

“…Some symptoms were reported less frequently among vaccinated than unvaccinated mpox patients. Gushchin et al [66] studied the optimal duration following the first dose of vaccination to provide protection against MPXV infection. Within two weeks of receiving the first dose of MVA-BN, the majority of postvaccination mpox infections occurred before complete efficacy was expected to have been reached.…”

Evaluation of Cross-Immunity to the Mpox Virus Due to Historic Smallpox Vaccination

“…A mouse model of VACV infection suggested that CD4+ T-cell-dependent anti-VACV antibody production plays an important role in clearing the virus following acute infection, while in the absence of antibodies, CD8+ T cells can contribute to protection against the disease [3]. It is believed that the smallpox vaccine confers lifelong protection against severe disease [10], and studies carried out after smallpox eradication tried to estimate the waning effect by measuring the levels of immunological markers at different time-points post-immunization [11][12][13][14][15][16][17][18][19][20][21]. Nowadays, after smallpox eradication and the discontinuation of the vaccination campaign, the human population is largely unvaccinated.…”