एमपॉक्स

इन्फ्लुएंजा क्या है?

Mpox (previously known as monkeypox) is a viral zoonosis (an infection spread from animals to humans). It is caused by a virus that belongs to the ऑर्थोपॉक्सवायरस genus (which also causes the variola virus responsible for smallpox disease). Since the eradication of smallpox in 1980, mpox has become the most important orthopoxvirus affecting humans.

किन लक्षणों पर नज़र रखने की आवश्यकता है?

The incubation period of mpox is usually 7-14 days, but can be as short as 5 days or as long as 21 days. The initial symptoms include fever, headache, muscle aches, fatigue and lymphadenopathy. Lymphadenopathy in this early phase is a key feature of mpox.

1-3 days following the beginning of fever, a rash may develop, often beginning on the mouth and face, and then spreading to other areas of the body. The face is involved in 95% infections, followed by the palms of the hands and soles of the feet (75%). Oral mucous membranes are involved in 70% of cases, and involvement of the genitalia is also common (30%).

The rash is initially characterised as being erythematous (reddened) and macular (flat), which then develops papular features (raised areas) and turns into well-demarcated pustules and vesicles (blisters). These then dry into crusts and fall off. The number of lesions is highly variable, ranging from a couple to over a thousand.

The infection is usually self-limiting with symptoms lasting from 2-4 weeks. Complications can include secondary infection such as cellulitis, sepsis, infection of the cornea (which can threaten vision), bronchopneumonia and encephalitis. The case fatality ratio is between 3-6%. More severe illness can occur in immunocompromised people.

यह कैसे संचारित होता है?

Mpox is spread via either animal-to-human transmission (zoonotic) or human-to-human transmission.

Zoonotic transmission involves direct contact with the bodily fluids, blood, or lesions (cutaneous or mucosal) of infected animals (often through bites or scratches). This is most common for people living near or within forest areas with exposure to infected animals.

Human-to-human transmission involves close contact with respiratory secretions (through activities such as kissing), the skin lesions of an infected person (by touching or sexual contact), or through contact with contaminated objects such as linen or clothing. Droplet particle transmission requires prolonged face-to-face exposure, placing household contacts at highest risk. This can be minimised by isolating away from other members of the household. Infections during pregnancy can be transmitted to the baby.

Healthcare workers caring for individuals with mpox must undertake infection control precautions and handling of laboratory specimens should be by suitably trained staff.

एपिडेमियोलॉजी (महामारी विज्ञान)

Mpox is very common in West and Central Africa, often in areas with tropical rainforests. However, there are currently outbreaks in many other countries across the globe including Australia and parts of Europe and the United Kingdom.

टीके

There are two types of vaccines available for use in Australia for the prevention of mpox:

• ACAM2000 – 2nd generation, live-attenuated vaccine
• JYNNEOS (MVA-BN) – 3rd generation, non-replicating vaccine.

Both vaccines are formulated using the vaccinia virus, a poxvirus related to smallpox and mpox.

JYNNEOS (MVA-BN) can be administered either subcutaneously (preferred) or intradermally. ACAM2000 must be administered via a percutaneous route which can only be performed by a provider who is trained in this complex technique. ATAGI preferentially recommends JYNNEOS (MVA-BN) vaccine due to the ease of administration and decreased likelihood of side effects.

Recommendations

Vaccines can be administered as either primary preventative vaccination (PPV) or post-exposure preventative vaccination (PEPV). For PEPV, vaccination within 4 days is recommended to provide optimal protection against the development of mpox infection. Vaccination between 4-14 days following exposure may lessen the severity of disease.

Vaccination is currently recommended for the following groups:

• sexually active gay, bisexual or other men who have sex with men (GBMSM), including transgender and gender diverse people
• sex workers
• people living with HIV or other immune suppressive conditions if at risk of mpox exposure
• laboratory personnel working with orthopoxviruses
• high-risk contacts of a confirmed case of mpox.

Vaccination may also be considered for:

• healthcare workers at risk of exposure to patients with mpox
• regular sexual partners of GBMSM, sex workers and people living with HIV.

Contraindications

Anyone with a history of तीव्रग्राहिता to a previous dose of the vaccine to be administered or anaphylaxis to a component of the vaccine to be administered should not be vaccinated.  Due to the risk of vaccine associated disease, ACAM2000 is contraindicated for those with immunocompromise or those who are गर्भवती.

Individuals with active eczema, atopic dermatitis or other exfoliative skin conditions should not receive ACAM2000 due to the risk of developing eczema vaccinatum (a reaction to smallpox vaccination experienced by people with eczema/atopic dermatitis resulting in a severe rash and systemic illness).

एहतियात

Subcutaneous vaccination is preferred over intradermal in individuals with a history of keloid scarring.

Individuals receiving ACAM2000 as PPV should consider an interval of 4 weeks between vaccination and administration of COVID-19 vaccines due to the rare risk of मायोकार्डिटिस / पेरिकार्डिटिस.

Table 1: Vaccine brands, dose and route 

* subcutaneous and intradermal routes are considered interchangeable to complete a primary course; when vaccinating post-exposure (PEPV) using a subcutaneous route is preferred for the first dose
^ only immunisation providers with appropriate training and experience should administer vaccines via an intradermal route
# percutaneous administration involves using a bifurcated needle and scarification technique which requires specialised training and accreditation
Ω for full aftercare instructions, refer the product information

संसाधन

विक्टोरियन कार्यक्रम की जानकारी

• Victorian Department of Health: Mpox [includes information on where to access vaccines]

अन्य संसाधन

• Australian Government Department of Health and Aged Care: Mpox resources
• Mpox virus infection: CDNA National Guidelines for Public Health Units
• Better Health Channel: Mpox