Officials at the Centers for Disease Control and Prevention on Friday challenged the idea that monkeypox virus could be spread through the air, saying the virus is usually transmitted through direct physical contact with contaminated materials or wounds from a patient.
The virus can also be transmitted through respiratory droplets expelled by an infected patient who comes into physical contact with another person, they said. However, it cannot stay in the air over long distances.
Experts disagree on airborne transmission of viruses, but some said the agency had not fully evaluated the possibility that respiratory droplets, large or small, could be inhaled at a shorter distance from a patient.
The World Health Organization and several experts said that although “short-range” airborne transmission of monkeypox is rare, it is possible and possible. guarantees the measures. in England Monkey flower is on the list “High-consequence infectious diseases” that can spread through the air.
“Airborne transmission may not be the dominant route of transmission or very efficient, but it can still happen,” said Linsey Marr, an expert in airborne viruses at Virginia Tech.
“I think the WHO is right, and the CDC’s message is misleading,” he added.
CDC officials said at a news conference that the monkeypox epidemic in the United States had risen to 45 cases in 15 states and the District of Columbia. The global scoreboard has increased rapidly since 13 May, when the first case was reported, to over 1,450. At least 1,500 cases are still under investigation.
Historically, people with monkeypox have reported flu-like symptoms before a characteristic rash appears. But the agency’s director, Dr. Rochelle Walensky said Friday that some patients in the current outbreak first developed a rash, and some never experienced these symptoms.
He said no deaths have yet been recorded in the current outbreak.
Questions about airborne transmission of the monkeypox virus are important because answers will be based on recommendations for masking, ventilation and other protective measures should the outbreak continue to grow.
The CDC said on Thursday that monkeypox “does not linger in the air and is not transmitted during short-term shared airspace.” After a statement New York Times article On Tuesday, scientists described uncertainties about the transmission of the virus.
Dr. “What we do know is that those diagnosed with monkeypox in this current outbreak have described close and sustained physical contact with other infected people,” Walensky said Friday. “This is consistent with what we’ve seen in previous outbreaks and what we’ve learned from studying this virus and closely related viruses over the decades.”
But other experts said monkeypox has not been adequately studied and there have been occasional airborne transmission incidents. reported for the closely related smallpox virus. in 2017 monkeypox epidemic In Nigeria, scientists said at a recent WHO conference that infection occurred in two healthcare workers who had no direct contact with patients.
CDC officials acknowledged that few patients in the current outbreak did not understand when or how they contracted the virus.
A specialist in airborne virus transmission at the University of Maryland, Dr. Donald Milton said the agency was right to reassure the public that the epidemic is not a threat to most people because monkeypox is not as contagious as the coronavirus.
Dr. Milton said airborne transmission poses no risk to anyone but emergency caregivers, but cautioned that dismissing the possibility entirely is “the wrong way to do it.”
When a virus is found in saliva or saliva the respiratory systemDr. Milton and other experts said monkeypox can be expelled in respiratory droplets when talking, singing, coughing or sneezing, as shown.
Droplets can be heavy and fall quickly on objects or people, or they can be small and light, remaining in the air for long periods and distances. The CDC’s assessment depends in part on whether the virus is present only in large droplets or in very small droplets called aerosols.
A similar discussion arose at the start of the coronavirus pandemic, when the agency and WHO focused on large droplets as the main route of transmission. But aerosols turned out to be a major driver.
The new CDC guideline on monkeypox has described respiratory droplets emitted by patients as “rapidly falling secretions from the air.”
But Lidia Morawska, an air quality expert at Queensland University of Technology in Australia, said the virus can be found in “respiratory particles of any size”, not just in large droplets.
“In my view, the claim that the virus is transmitted only through large droplets and poses a risk of infection only at close range has no basis,” he wrote in an email.
CDC officials said Friday that patients in the current outbreak appear to have been infected through close and sustained contact. However, this can be difficult to determine.
What You Should Know About Monkeypox Virus
What is monkey flower? monkey disease A virus endemic to parts of Central and West Africa. It is similar to smallpox, but less severe. It was discovered in 1958 after outbreaks occurred in monkeys hired for research, according to the Centers for Disease Control and Prevention.
Dr. When people are in close contact, it may be impossible to distinguish whether a virus is transmitted through touch, spraying large droplets or inhaling aerosols, Marr said.
“The occurrence of transmission in such cases does not define how the virus is passed from one person to another,” he added. If transmission can occur by spraying respiratory droplets, “then it almost certainly also occurs by inhalation of aerosols.”
Still, most experts agree that regardless of the contribution of inhaled aerosols, monkeypox is not transmitted over distances where the coronavirus or measles virus may exist.
Dr. “I agree that most monkeypox transmission is by touch — most likely direct contact between mucous membranes,” Milton said.
But “CDC seems to be stuck with outdated terminology,” he said. “We really need to talk about transmission, using terms that clearly say how it is through touch, spray or inhalation.”
CDC itself accepts the possibility Short-range airborne transmission is recommended by clinicians. The agency recommends that patients wear masks and that caregivers wear N95 respirators, which are necessary to filter aerosols.
It also warns that “procedures that are likely to spread oral secretions should be performed in an airborne infection isolation room.”
There is evidence that monkey flower can do it. survive in aerosols and this inhaled virus to cause illness in monkeys. However, airborne transmission may not be ideal for monkeypox virus.
Dr. Patients may not release too much virus in aerosols, the virus may not remain contagious for long, or the amount of virus inhaled may be too high to infect a person, Marr said.
In this case, airborne transmission is likely to occur only between people who are close for a long time. Still, health officials in the UK, like those in the United States, said many patients did not know when or where they could become infected.
Dr. If they were infected without close contact, “airborne transmission is more likely than we anticipated,” Marr said.
