World Health Organization (WHO) has been doing surveillance of the multi-country outbreak of Mpox (formerly monkeypox) caused by the monkeypox virus of Orthopoxvirus genus in the Poxviridae family. It was discovered in Denmark among monkeys kept for research in 1958 and the first reported human case was in the Democratic Republic of the Congo. It has 2 genetic clades - clades I and II. (1) In 2022-2023 we witnessed a global outbreak caused mostly by the Clade IIb virus.

Transmission:

Incubation period: 1-21 days.

Signs & symptoms: Fever, rash, sore throat, lymphadenopathy. The rash begins as a macule which develops into a blister, then crusts and wanes.

Diagnosis: Detection of viral DNA by polymerase chain reaction (PCR).

Treatment & Vaccination: Antivirals like Tecovirimat and vaccination is available.

Outbreaks around the world

• After 1970- sporadic cases in Africa.

• 2003- In the United States of America (clade II).

• Since 2005- thousands of suspected cases in the DRC every year.

• 2017- re-emerged in Nigeria and continues to spread in natives and in travellers.

• May 2022- First in Europe, America and then all six WHO regions about 87,000 cases and 112 deaths.

WHO as a part of its surveillance, publishes a series of reports showcasing the Mpox multicountry outbreak highlighting efforts undertaken to mitigate the spread and for global health protection.

Highlights of the report

• No longer a Public Health Emergency of International Concern (PHEIC) under the International Health Regulations.

• A cumulative total of 88,288 lab-confirmed cases and 149 deaths were reported from 1st January 2022 to 11 July 2023. (2)

• South-East Asia Region witnessed an increase in cases, mainly from Thailand.

• ‘Eliminating Mpox: Placing affected populations at the heart of our response’- a campaign launched by WHO European region for control and elimination.

Table 1: Number of cumulative confirmed Mpox cases and deaths reported to WHO(2)

• 96.2% of cases are males, with a median age of 34 years as of 11th July 2023. (2)

• Among cases, 84.1% have self-identified as gay, bisexual and MSM. The high proportion of males can be indicative of transmission among MSM.

• Among all transmissions reported, 82.1% were skin and mucosal contact during sex followed by non-sexual contact. (2)

• Most common symptom- rash followed by fever and generalized/genital rash.

• The duration of immunity following primary infection and protection from re-infection is currently unknown. There are reinfections and further research is warranted in this area.

• Vaccination: New Orthopoxvirus vaccines are developed such as Non-replicating vaccines (MVA-BN), minimally replicating vaccines (LC16) or replicating vaccinia-based vaccines (ACAM2000). (3)

• MVA-BN - 2-dose subcutaneous injection (0.5ml) given at least 4 weeks apart.(3)

• LC16 and ACAM2000 - single dose using scarification method with a bifurcated needle. (3)

WHO recommendations

1. Gay, bisexual, or MSM with multiple sexual partners

2. Those with multiple casual sexual partners, Sex workers

3. Health workers and laboratory personnel

4. Outbreak response team members.

• Cases have been reported in persons who have been vaccinated. 19 cases in early 2023 were reported in the Centre-Val de Loire region in France. 10 of them had received 2 doses, the rest had smallpox vaccination in childhood and received the MVA-BN vaccine.

• WHO will publish a Global strategic framework for enhancing control and achieving the elimination of human-to-human transmission of Mpox to prevent community transmission, advance Mpox research and minimize zoonotic transmission.

• Situation update of South- East Asia Region (SEAR):

Laboratory

• 4 reference laboratories were identified, in India, Thailand and Australia.

• A global external quality assessment (EQA) programme for virus testing is arranged.

Clinical Management

• National guidelines for clinical management were developed by Member states and supported by WHO interim guidance.

• Online courses and webinars were conducted by WHO for clinicians and health workers.

Infection Prevention and Control (IPC)

• WHO engaged with Member States to review the draft outline of the Global Strategy on IPC in health and long-term care settings, 2023–2031 providing an opportunity to reinforce the importance of IPC.

Contributing factors for breakthrough infections

Way forward

The key challenges including continued exposure, inadequate reporting, the need to raise awareness and improved surveillance have to be addressed. Even though no longer PHEIC, Mpox continues to be a significant global health concern and uncertainties regarding the disease still remains. Sustained long-term strategies are the need of the hour.  Vaccines are effective when it’s merged with preventive measures. It is important to continue to promote and implement all appropriate public health measures irrespective of vaccination status. Strong international coordination and cooperation and community engagement should be there for effective interventions.

References:

1. Mpox (monkeypox): Available from: https://www.who.int/news-room/fact-sheets/detail/monkeypox (Accessed on 30th June 2023)

2. Multi-Country outbreak of mpox: Available from: file:///C:/Users/MY%20BOOK/Downloads/20230712_mpox_external-sitrep_26.pdf

3. Vaccines and immunizations for Monkeypox: Available from: file:///C:/Users/MY%20BOOK/Downloads/WHO-MPX-Immunization-2022.3-eng.pdf (Accessed on 15th July 2023)