Mpox and Covid are very different, virologist Christopher Barbara says

The Maltese public should not compare their experience with the Covid-19 to the current mpox outbreak, virologist Christopher Barbara told The Malta Independent on Sunday.Barbara said that not only are Maltese healthcare workers vigilant for mpox and

By: independent.com.mt

Aug 25 2024
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Mpox and Covid are very differ

The Maltese public should not compare their experience with the Covid-19 to the current mpox outbreak, virologist Christopher Barbara told The Malta Independent on Sunday.

Barbara said that not only are Maltese healthcare workers vigilant for mpox and are following infection control guidelines with various diagnostic testing methods at Mater Dei, but anti-viral mpox medication is also available and mpox vaccines are in use.

Last Monday the Health Ministry said that no cases of mpox, previously known as monkey pox, have been reported on the island.

"Readers should not be alarmed at all at this stage and should not compare the experiences which we have been through with the Covid pandemic as the viruses are completely different," Barbara said.

Mpox was declared an "international health emergency" by the WHO on 14 August. "An international health emergency means that there is a situation of a public health crisis, which may spread globally," he said. "This situation could potentially constitute a public health risk to other countries beyond the affected state and would require a co-ordinated international response."

"Malta has an obligation under the 2005 International Health Regulations (IHR) to respond promptly following a declaration by WHO of an international health emergency. In fact, the office of the Superintendence of Public Health, within the Ministry of Health and Active Aging, was already alerted to this threat and discussions were held by stakeholders to co-ordinate a response and prepare for any possible outcomes. Healthcare workers in Malta have included mpox in their radar for surveillance of infectious diseases."

Barbara was asked why mpox suddenly became a current global concern. "Mpox has become a global concern because of the current behaviour exhibited by the virus. This new clade (group of organisms from the same ancestor) warrants vigilance. We are now looking at altered transmissibility and infectivity and finding the best measures to halt its spread."

Barbara said "the mortality rate for mpox remains below 4%, however, some mpox outbreaks have killed up to 10% of people who get sick and hence caution prevails".

"The mpox outbreak in the US (in 2023) was managed well by early contact tracing and vaccination primarily," he said. "Healthcare workers were made aware of the signs and symptoms and diagnostic facilities were immediately available. Hence the outbreak was, on the whole, curtailed."

According to statistics published by the US Centre for Disease Control (CDC) the total mpox cases in this outbreak in the US amounted to 32,063 and there were 58 deaths, he said.

Barbara was asked to explain apparent links between mpox to the eradicated smallpox. "The smallpox virus and the monkey pox virus are closely related and belong to the Orthopoxvirus family," he said. "Smallpox, which is caused by the variola virus, was one of the most devastating diseases known, and caused millions of deaths before it was eradicated. On the other hand, mpox is much less deadly. It presents with headaches, fever, fatigue and body aches, swollen lymph nodes and skin vesicles."

Barbara said that "clinically, mpox causes swelling in the lymph nodes but there is no lymphadenopathy in smallpox. The mpox virus replicates in the lymph nodes and spreads to the blood stream. From there it spreads to the liver and spleen and later to the lungs."

Following the Covid-19 pandemic, which made people being familiar with droplet or aerosol transmission, Barbara said: "While the recent swine flu and Covid-19 pandemics were classically sparked by airborne viruses and infected droplets from persons who were even apparently asymptomatic, mpox is spread primarily through close skin to skin contact with other infected people, animals or their contaminated fomites [infected objects]." He pointed out, however, "the pox virus often causes visible vesicles on the skin, hence making it less likely for others to be in close contact".

"Mpox was originally transmitted from animals to humans but now passes between humans. The transmission occurs via contact with the skin lesions or contaminated surfaces, clothing, bed linen or other contaminated fomites. Hence sexual transmission is included here." He also pointed out, "it is possible that breathing or talking close to an infected person may be a cause of transmission".

Asked which cohorts (groups of people in society such as the young, pregnant, etc.) are most vulnerable to mpox infection, Barbara said that "health care workers at risk are following infectious controlled guidelines. Not only would they wear PPE in handling these patients, but they are practising the procedure of donning and doffing PPE and other practices. Of course, hand-washing techniques remain of utmost importance". He said: "People at highest risk include those with multiple sex partners but there are also risks of infection from animal bites or scratches or eating infected animals."

Barbara said that currently "there are various kits to detect mpox including antigen tests, lateral flow tests as well as molecular tests. These are also commercially available as home kits, but I believe these are not available locally. Mater Dei Hospital uses molecular tests with high sensitivity with specificity." He said that to treat mpox "antivirals are available for mpox as well as prevention for vaccination" but pointed out "antibiotics have no effect on this virus".

Giving details on the currently available vaccination, Barbara said: "Vaccines are available in a two-dose regimen, and these are recommended for exposed people, high risk groups and contact cases. These vaccines are conventional vaccines."

As a take-away message, Barbara emphasised the importance of disease surveillance, which monitors infections in all regions around the world. "We, in Malta, form part of this exercise. If there is any virus, which is changing its behaviour, one should study it more closely and inform other countries of any potential threats. This mechanism of action will prevent this spread of infection and will ensure a better quality of life both mentally and physically."