As of September 21, the current monkeypox epidemic has infected 62,532 people in 105 countries. Still, the World Health Organization (WHO) has not yet classified the current caseload as a pandemic.
But can this change? Given its spread, monkey flower be a pandemic?
The answer to this question depends on the definition of “pandemic”. A pandemic is a “worldwide epidemic” in which there are large numbers of cases or outbreaks in many countries, Rachel Roper, professor of microbiology and immunology at East Carolina University in Greenville, North Carolina, told Live Science in an email.
“I think it’s a matter of opinion on how many cases you should have in how many countries,” Roper said. this Centers for Disease Control and Prevention (opens in new tab) (CDC) defines a pandemic as “a disease event that affects a large number of people, usually involving person-to-person transmission, in which there are more cases of disease than expected to spread to several countries or continents”.
There is always the possibility that something like the genetic code of the virus will change, but several factors reduce the chances of monkeypox becoming a pandemic. Nowhere near the toll of the monkeypox COVID-19 pandemic will be certain, even if experts tell Live Science.
Historically, monkeypox was not very contagious and outbreaks were small.
Roper said Monkeypox (sometimes abbreviated as MPXV or MPX) is “much less contagious than COVID.” Typically, the chain of transmission of monkeypox was short—one MPXV case infected a maximum of seven people before dying, so in the past outbreaks were short-lived, Roper said. Monkeypox was first documented to infect humans in 1970, and outbreaks have since been “somewhat minor,” excluding the current pandemic, he said. In countries where it is endemic, monkeypox is always found in animal hosts and typically spreads between humans only when they are caught from animals and begin to transmit it to other humans.
However, an analysis of monkeypox genomes from the current outbreak published June 24 in the journal Nature Medicine (opens in new tab)Roper suggests that the version of the virus currently in circulation has been passed from person to person in an uninterrupted chain of transmission since 2017. This indicates that the average chain of transmission is increasing, Roper said.
However, for monkeypox, the reproduction number (R0), or the number of people directly infected by each infected person, has historically been less than 1, meaning any epidemic will eventually go out without active disease control measures (although For currently circulating omicron variants of SARS-CoV-2, the virus that causes COVID-19, the R0 is estimated to be between six and 10. Speech (opens in new tab).) But researchers don’t know the R0 for the currently circulating version of monkeypox, according to one study. June 2022 paper (opens in new tab) in the journal Lancet Infectious Diseases.
It’s hard to say why monkeypox is infecting so many people, he added. It could be because mutations make it more contagious or because it enters new populations with different behaviors as a whole or risk factors that increase transmission rates, Roper said.
For example, in African countries where monkeypox is endemic, the virus was not known to be spread through men who had sex with men before, Roper said. But the current epidemic primarily affects men who have sex with men and spread through sexual and other close physical contact. world Health Organization (opens in new tab) (WHO).
Monkeypox mutates rather slowly
Monkeypox is a virus. DNA, as opposed to being composed of single-stranded ribonucleic acid (RNA). This is important because DNA replication is less error-prone than RNA transcription, so monkeypox mutates more slowly than its counterparts such as SARS-CoV-2 or HIV. This gives monkeypox viruses less opportunity to evolve to become more infectious than RNA viruses. American Society for Microbiology (opens in new tab).
Yet, for a smallpox virus, monkeypox is rapidly developing mutations, according to June Nature Medicine genome analysis. Compared to strains circulating in 2018 and 2019, the currently circulating virus has 50 mutations that were most likely caught while circulating in humans, according to the article. This is between six and 12 times the expected number of mutations, depending on the typical mutation rate for poxviruses, the paper authors said.
Not a lung virus
Roper said the virus that causes COVID-19 is “largely respiratory.” “The main target organ is the lungs.” Roper said SARS-CoV-2 spreads when an infected person sneezes, coughs or even just breathes. In contrast, monkeypox is spread primarily through “direct contact with monkeypox rash, scabs, or bodily fluids from a person who has monkeypox,” according to the Centers for Disease Control and Prevention (CDC). The virus can also be spread when a person touches objects and surfaces that have been used by someone infected with monkeypox.
“Monkeypox is very inefficient in how it spreads,” Rodney Rohde, MD, professor and chair of clinical laboratory science at Texas State University, told Live Science. “You have to be in really close, skin-to-skin contact, or maybe in contact with fomites like bed linen or clothing. And it actually takes a while to happen, so a few hours of contact, whereas [for] An aerosolized virus can be instantaneous – someone sneezes or coughs in a room and you inhale it and maybe 8, 10, 12 people get it.”
We already have vaccines and treatments for monkeypox
Two vaccines, JYNNEOS and ACAM2000, are approved for use against monkeypox in the USA. Live Science previously reported.
Although there is no specific treatment for monkeypox, HCM (opens in new tab)antiviral drugs developed to fight smallpoxLike tecovirimat (TPOXX), it can be recommended for debilitated people. immune systems.
The availability of vaccines and treatments combined with other factors, such as the low mortality rate of the currently circulating monkeypox strain, should be possible to slow the rate of infection and limit deaths, Rohde said. The mortality rate of the circulating monkeypox strain in the current outbreak has historically been about 1%. HCM (opens in new tab). But the current epidemic may be far less deadly; According to WHO figures at the end of September, the mortality rate is 0.04%. While these numbers are still a rough estimate, they suggest that even if monkeypox becomes an epidemic, the transmission of monkeypox would be much, much lower than COVID-19. “It could be considered an epidemic at some point because of the number of countries with cases and the linear increase in cases we’re seeing,” Rohde said. Said. “But I don’t believe this will be the kind of global death crisis we’ve seen with COVID.”
Originally published on Live Science.