Is monkeypox looking like Covid-sized threat?

In just the past few weeks, at least 92 confirmed and 28 suspected cases of monkeypox have been reported across Europe, Canada, Israel, the US and Australia. And that number stands to grow as surveillance expands, Maria Van Kerkhove of the World Health Organization (WHO) said.
This is concerning, but no reason for anyone to panic. The global response to these case clusters is so far working as it should. Scientists are sequencing and analysing the genes of virus samples. Public health agencies are tracking down people who might have been exposed. Education efforts are underway to make health-care workers and any vulnerable communities aware of the outbreak. And governments are preparing to deploy vaccines and antivirals as needed.
Nevertheless, the curious cases raise questions about why this transmission is happening now and who is at risk.
Scientists are scrambling to answer this key question. Two strains, or clades, of monkeypox are known to exist, and the one currently circulating seems to be the milder West Africa one.
In the past, monkeypox cases have typically arisen via animal-to-human transmission in Central or West Africa, where the virus is
endemic. “It’s what we call a dead-end infection,” says Grant McFadden, director of Arizona State University’s Biodesign Center for Immunotherapy, Vaccines and Virotherapy. “It can spread from human to human by direct contact, but the chain tends to peter out pretty quickly.”
This makes the current degree of human-to-human transmission concerning. One possible explanation is that the virus simply has had more opportunities to infect people. Routine administration of the smallpox vaccine, which also protects against monkeypox, was ended in the US and other countries in the 1970s. (The world was declared free of smallpox in 1980.) This means that a sizable chunk of the population has no existing immunity to monkeypox.
People born during the era of routine smallpox vaccinations might retain some protection, McFadden says. Immune responses to the smallpox vaccine are known to be long-lived. But how well that correlates to monkeypox is an open question.
Several clusters of cases are concentrated in a community of men who have sex with men, suggesting that a gathering or event might have kicked off a chain of transmission. Another theory for the rise in cases is that something in the virus itself has changed to make it more transmissible. Scientists already have several rough drafts of the viral genome taken from patients, including samples from Portugal, Belgium and the US, and are looking for any changes that might make it better at infecting people. Such changes are unexpected, because monkeypox is a DNA virus and therefore has a genome more stable than that of an RNA virus such as Sars-CoV-2.
So far, nothing unusual has been detected in the monkeypox gene sequences, says Gustavo Palacios, a virologist at the Icahn School of Medicine at Mount Sinai in New York City, who until last year was a biopreparedness expert at the US Army Medical Research Institute of Infectious Diseases.

—Bloomberg