Officials at the Centers for Disease Control and Prevention on Friday said monkeypox virus is usually transmitted by patient pain and direct physical contact with contaminants, suggesting that monkeypox virus can spread in the air. I opposed it.
The virus can also be transmitted by respiratory droplets that are excreted by the infected patient’s physical contact with others, they said. But it can’t stay in the air over long distances.
Experts on the aerial transmission of the virus disagreed, but some said authorities did not fully consider the possibility of respiratory droplets, large or small, being inhaled at shorter distances from the patient.
The World Health Organization and several experts say that “short-range” aerial transmission of monkeypox appears to be rare, but it is possible. Guarantee precautionary measures..UK too The list includes monkeypox An example of a “high impact infection” that can spread in the air.
Linsey Marr, an aerial virus expert at Virginia Tech, said:
“I think WHO understands that right. The CDC message is misleading,” she added.
A CDC official said at a news conference that monkeypox outbreaks have spread to 45 in 15 states and the District of Columbia in the United States. Global aggregates have risen rapidly to over 1,450 since May 13, when the first case was reported. At least 1,500 cases are still under investigation.
Historically, people with monkeypox have reported flu-like symptoms before the onset of the characteristic rash. However, some patients with the current outbreak first developed the rash, and some had no of these symptoms, said agency director Dr. Rochelle Walensky on Friday. I did.
No deaths have yet been recorded in the current outbreak, she said.
Questions about the aerial transmission of the monkeypox virus are important. That’s because the answer affects recommendations for masking, ventilation, and other protective measures as the outbreak continues to spread.
The CDC said Thursday that monkeypox “is not known to stay in the air and will not be transmitted in a short period of time in the shared airspace.” The statement followed Tuesday’s New York Times article, where scientists explained the uncertainty about the transmission of the virus.
“What we know is that people diagnosed with monkeypox in this current outbreak explained close and lasting physical contact with other people infected with the virus,” Warren said. Dr. Ski said on Friday. “This is consistent with what we have seen in previous outbreaks and what we know from decades of research into this virus and its closely related viruses.”
However, monkeypox has not been well studied, other experts said, and occasional episodes of airborne infections. Has been reported For the closely related smallpox virus. In 2017 Outbreak of monkeypox In Nigeria, two health workers who were not in direct contact with the patient were infected, scientists said at a recent WHO meeting.
CDC officials admitted that some of the current cases are unaware of when and how they were infected with the virus.
Dr. Donald Milton, an expert on aerial virus infections at the University of Maryland, says monkeypox is not as contagious as the coronavirus and has the right to reassure the public that this outbreak is not a threat to most people. Stated.
Dr. Milton said airborne infections are unlikely to pose a risk to anyone other than direct caregivers, but denying that possibility altogether is “the wrong way to do it.” I warned.
If the virus is present in saliva or saliva AirwaySpeaking, singing, coughing, and sneezing, as shown by monkeypox, can be excreted by respiratory droplets, Dr. Milton and other experts said. ..
Droplets can be heavy and quickly fall on an object or person, or they can be small and light and stay in the air for extended periods of time. The evaluation of the CDC is partially determined by whether the virus is present only in large droplets or in very small droplets called aerosols.
Similar discussions took place when the coronavirus pandemic began, when authorities and WHO focused on large droplets as the primary transmission route. However, aerosols turned out to be the main driving force.
The new CDC guidance on monkeypox describes the respiratory droplets released by the patient as “secretions that quickly shed from the air.”
However, Lydia Morauska, an air quality expert at the Queensland Institute of Technology in Australia, said the virus “can be present in respiratory particles of all sizes,” not just large droplets.
“In my view, there is no basis for a statement that the virus is transmitted only by large droplets and indicates a risk of infection only at close range,” she wrote in an email.
A CDC official said on Friday that the current outbreak appears to have been infected by close and sustained contact. However, this can be difficult to determine.
What you need to know about monkeypox virus
What is monkeypox? Monkeypox is a virus that is endemic in parts of Central and West Africa. Similar to smallpox, but less serious. According to the Centers for Disease Control and Prevention, it was discovered in 1958 after an outbreak occurred in monkeys kept for research.
If people are in close contact, it may not be possible to distinguish whether the virus was transmitted by contact, spraying large droplets, or inhaling aerosols, Dr. Ma said.
“Outbreaks of infection in such situations do not define how the virus is transmitted from person to person,” she added. If the infection can be caused by spraying respiratory droplets, “almost certainly by inhalation of aerosol”.
Still, most experts agree that monkeypox does not appear to be transmitted beyond the possible distance of coronavirus or measles virus, whatever the contribution of inhaled aerosols.
“I agree that most monkeypox infections are caused by contact — probably direct contact between the mucous membranes,” said Dr. Milton.
But “CDC seems to stick to the old term,” he said. “We really need to talk about communication using terms that clearly indicate how it happens — through touch, spray, or inhalation.”
CDC itself Recognize the possibility Of short-range aerial transmission in advice to clinicians. The agency recommends that the patient wear a mask and the caregiver who cares for the patient wears the N95 respirator required to filter the aerosol.
It also warns that “procedures that may spread oral secretions should be performed in an airborne isolation room.”
There is evidence of monkeypox Survive with aerosols And the inhaled virus Cause illness In a monkey. However, aerial infections may not be ideal for monkeypox virus.
The patient may not release many viruses in the aerosol, the virus may not remain infectious for a long time, or the amount of inhaled virus needed to infect someone may be too high, Said Dr. Ma.
In that case, aerial infections can only occur among people who are in close proximity for long periods of time. Still, UK health officials, like US health officials, say many patients do not seem to know when and where they were infected.
If they were infected without close contact, “there may be more airborne infections than we are aware of,” Dr. Ma said.
