Hygiene and disinfection measures for infections with monkeypox viruses (as of 27.05.2022)

Introduction

Monkeypox is a zoonotic viral disease caused by an infection with the monkeypox virus. This is an enveloped double-stranded DNA virus and belongs to the genus of orthopoxviruses of the Poxviridae family. The following explanations correspond to the current state of knowledge and must be continuously adapted to new scientific findings. The latest applicable recommendations must be observed.

Monkeypox is endemic in West and Central Africa and has so far only been found sporadically in other countries. Two different variants (clades) are known: West African and Central African. Humans are actually false hosts for monkeypox. Natural hosts are small mammals such as ground squirrels, gophers or rodents.

The symptoms are initially unspecific, often fever, headache and muscle pain, swollen lymph nodes (prodromal stage). Later, skin lesions also appear, which go through various phases [1]. It is assumed that the infectiousness lasts from the beginning of the prodromal stage at least until the crusts of the skin lesions fall off. The incubation period is 5 to 21 days. At up to 1% [1], the lethality rate of the West African variant is significantly lower than that of the Central African variant (up to 11%, usually children, data from Africa [2]). In most cases, the disease heals itself.

Epidemiology since May 2022

Since May 13, 2022, 332 travel-independent confirmed cases have been reported worldwide (source: https://monkeypox.healthmap.org/, accessed on May 27, 2022, 15:30). The cases are all attributable to the West African clade with a favorable prognosis. The largest cluster is currently in the United Kingdom (90 cases), followed by Spain (84) and Portugal (58). In Germany, there were 16 laboratory-confirmed cases from six federal states as of May 27, 2022 [3]. All cases affect men and sexual transmission is suspected in the majority of cases. The skin lesions first occurred in the urogenital and anal region and not on the hands and soles of the feet, as is usually the case. Severe cases or deaths have not yet been reported. In Germany, confirmed cases must be reported in accordance with Sections 6 and 7 of the Infection Protection Act (IfSG) [4].

According to current findings, the Robert Koch Institute considers the risk to the health of the general population in Germany to be low [3]. The possibility of generalized and severe courses with reduced immunity (e.g. infants and young children, pregnant women, patients with immunosuppressive treatment, atopic disposition, etc.) should be taken into account [2]. It is therefore also important to protect these population groups in particular.

Transmission routes and characteristics of monkeypox

Studies with the vaccinia virus - related to the monkeypox virus - showed that this virus can remain infectious on surfaces for up to 56 days [5]. Stability on textile fibers was also investigated with the vaccinia virus. According to these studies, the virus was still infectious after up to four weeks in wool fabric and after four to eight days in cotton; textiles contaminated with virus-containing dust even remained infectious for up to twelve weeks [6, 7]. In a recent publication by Adler et al., there are indications that the virus could be detected in some patients for up to three weeks (in one case from 2018 even up to 41 days) after diagnosis in the throat swab using a PCR test [8]. Whether this was just "residual nucleic acid" or infectious virus was not investigated.

Transmission

Human-to-human transmission occurs primarily through close (skin) contact via burst blisters, e.g. during sexual intercourse or, in the case of blisters in the mouth, also during kissing. In addition, transmission is possible via infectious material (e.g. via bed linen [skin/scab particles], towels, clothing, hand contact surfaces) and via the hands, and also via larger respiratory droplets. The transmission of monkeypox virus via semen, urine, stool, blood and tear fluid has not yet been conclusively clarified, although positive PCR test results were found in some of these materials in a recent study [8]. The question of airborne transmission or drift has also not yet been clarified. Therefore, windows should only be ventilated with the door closed (no cross ventilation).

The longest chains of infection that have been observed so far involved six to nine people [9].

Preventive measures

Vaccination

Various options are currently being discussed in Germany, including post-exposure prophylaxis for people with an increased risk of a severe course and the vaccination of healthcare staff who come into contact with monkeypox patients. The Standing Committee on Vaccination at the Robert Koch Institute (STIKO) will draw up a recommendation on this.

It is assumed that older people who were vaccinated before the smallpox vaccine was discontinued are protected to a certain extent against infection with monkeypox and a very mild course is likely.

Basic hygiene and disinfection

Measures for the possible isolation and quarantine of infected persons and contact persons are based on the specifications of the responsible health authority [10].

Smallpox viruses are enveloped viruses that can be inactivated by disinfectants with limited virucidal efficacy. As against SARS-CoV-2, disinfectants with proven "limited virucidal" efficacy are therefore generally suitable for disinfection. Products with "limited virucidal PLUS" and "virucidal" efficacy can also be used. Effective products for targeted or routine disinfection are included in the VAH disinfectant list or, for hand disinfection, also in the Robert Koch Institute's disinfectant list.

Priv.-Doz. Dr. Maren Eggers (VAH, GfV, DVV)1, Prof. em. Dr. med. Martin Exner (VAH, DGKH), Dr. Jürgen Gebel (VAH), Carola Ilschner (VAH), Prof. Dr. Holger F. Rabenau (GfV, DVV), Dr. Ingeborg Schwebke (GfV, DVV)
Priv. Doz. Dr. Maren Eggers (corresponding author) Laboratory Prof. Gisela Enders MVZ GbR, Head of Virology Rosenbergstr. 85 70193 Stuttgart
E-mail: m.eggers@labor-enders.de
Prof. em. Dr. med. Martin Exner, University Hospital Bonn, Dr. Jürgen Gebel (VAH), University Hospital Bonn, Carola Ilschner (VAH), University Hospital Bonn, Prof. Dr. Holger F. Rabenau, University Hospital Frankfurt, Dr. Ingeborg Schwebke, Berlin

Literature

1 Nitsche A, Schrick L, Schaade L. Human infections with monkeypox. Aviation and Travel Medicine 2019;26:18-24. Retrieved May 27, 2022.
2 WHO. Multi-country monkeypox outbreak in non-endemic countries. As of May 21, 2022. Retrieved May 27, 2022.
3 RKI. International monkeypox outbreak: Assessment of the situation in Germany. May 27, 2022. Retrieved on May 27, 2022.
4 RKI. Non-travel-associated cases of monkeypox in Europe and North America. Epid Bull 2022;20:15-16. Retrieved May 27, 2022.
5 Wißmann JE, Kirchhoff L, Brüggemann Y, Todt D, Steinmann J, Steinmann E. Persistence of Pathogens on Inanimate Surfaces: A Narrative Review. Microorganisms. 2021;9(2):343. published 2021 Feb 9. doi:10.3390/microorganisms9020343
6 Sidwell RW, Dixon GJ, McNeil E. Quantitative studies on fabrics as disseminators of viruses. I. Persistence of vaccinia virus on cotton and wool fabrics. Appl Microbiol. 1966 Jan;14(1):55-9. doi: 10.1128/am.14.1.55-59.1966
7 Sidwell RW, Dixon GJ, McNeil E. Quantitative studies on fabrics as disseminators of viruses. 3. persistence of vaccinia virus on fabrics impregnated with a virucidal agent. Appl Microbiol. 1967;15(4):921-927. doi:10.1128/am.15.4.921-927.1967
8 Adler H, Gould S, Hine P et al. Clinical features and management of human monkeypox: a retrospective observational study in the U.K. The Lancet Infectious Diseases, 24 May 2022 online first. DOI:https://doi.org/10.1016/S1473-3099(22)00228-6. Accessed May 27, 2022.
9 WHO. Monkeypox. Key facts. As of May 19, 2022. Retrieved May 27, 2022.
10 RKI. Monkeypox: Suspicion clarification and measures. Guidance for physicians. As of May 25, 2022. Retrieved May 27, 2022.
11 RKI. Recommendations of the RKI on hygiene measures in the treatment and care of patients with a

Citation reference:

Eggers M, Exner M, Gebel J, Ilschner C, Rabenau H, Schwebke I. Joint communication from VAH and the Virus Disinfection Commission of DVV and GfV: Efficacy of disinfectants against monkeypox viruses. Status 27.5.2022. Available at www.vah-online.de and https://g-f-v.org/komissionen/