The Centers for Disease Control and Prevention does not believe that the monkeypox virus can be spread through the air.
Respiratory droplets expelled by an infectious patient who comes into physical contact with another person could be used to transmit the virus. It can't stay in the air over a long distance.
The experts on airborne transmission of Viruses did not disagree, but some said that the agency had not considered the possibility that respiratory droplets, large or small, could be inhaled at a shorter distance from a patient.
According to the World Health Organization and several experts, it is possible for monkeypox to be transmitted in the air. Britain has a list of diseases that can spread through the air.
Linsey Marr is an expert on airborne Viruses at Virginia Tech.
The W.H.O. has it correct and the C.D.C.'s message is not.
The monkeypox outbreak in the US has grown to 45 cases in 15 states and the District of Columbia. Since May 13, when the first case was reported, the tally has gone up to more than 1,450. The cases are still being investigated.
People with monkeypox usually report flulike symptoms before a rash appears. Some patients in the current outbreak have developed the rash first, and some have not had any symptoms at all, according to the agency's director.
She said that no deaths have been recorded so far.
Should the outbreak continue to grow, the answers to questions about airborne transmission of the monkeypox virus will bear on recommendations for protection.
According to the C.D.C., monkeypox is not transmitted during short periods of shared airspace. Scientists described uncertainties about the transmission of the virus in a New York Times article.
According to Dr. Walensky, those who were diagnosed with monkeypox described close, sustained physical contact with other people who had the same disease. This is consistent with what we've seen before and what we know from decades of studying it.
Other experts said that monkeypox is poorly studied and that occasional episodes of airborne transmission have been reported. Scientists said at a recent W.H.O. conference that infections occurred in two health care workers who had no direct contact with patients.
C.D.C. officials acknowledged that a few patients in the current outbreak don't know how they contracted the disease.
The agency is right to assure the public that the outbreak is not a threat to most people because monkeypox is not as infectious as the coronaviruses.
It is not likely that anyone other than immediate caregivers will be at risk for airborne transmission.
Monkeypox can be expelled in respiratory droplets when it's present in saliva or in the respiratory tract.
The droplets can be heavy and quickly fall onto people, or they can be small and light and linger in the air for a long time. The C.D.C.'s assessment depends on whether the virus is present only in large droplets or in the very small aerosols.
The agency and the W.H.O. focused on large droplets as the main route of transmission in the beginning of the coronaviruses epidemic. Aerosols were a big driver.
According to the new C.D.C. guidance, the respiratory droplets that patients emit are secretions that drop out of the air quickly.
Lidia Morawska said that the virus can be present in respiratory particles of any size.
She wrote that there is no basis in the statement that the virus is only transmitted by large droplets.
C.D.C. officials said on Friday that patients in the current outbreak seem to have become infections. This can be hard to determine.
Monkeypox is what it is. In parts of Central and West Africa, there is a disease called monkeypox. It is not as bad as smallpox. According to the Centers for Disease Control and Prevention, it was discovered in the 50's.
The symptoms are what they are. People who have been bitten by the Monkeypox will have a rash that starts with red marks and grows into a large lump of flesh. Symptoms can take as long as three weeks after exposure to show and can last as long as four weeks. Vaccines and other treatments can be used to stop an outbreak.
What is it that makes it infectious? Some experts think that the virus could occasionally be airborne. It has spread in unusual ways this year and among populations that have not been at risk in the past.
I don't know if I should be concerned. There is a high chance that the virus will be spread during sexual contact, but there is a low chance that it will be transmitted in other ways. The virus can be fatal in a small percentage of cases, but most people recover quickly. Studies show that older adults may be able to protect themselves from vaccine-related diseases.
Dr. Marr said that it can be difficult to distinguish between touch, spray of large droplets and inhalation of aerosols.
She said that the occurrence of transmission doesn't mean how the virus got from one person to another is determined. If it can happen by the spray of respiratory droplets, then it can happen by the inhalation of aerosols as well.
Most experts agree that monkeypox doesn't seem to be transmitted over the distance that the coronaviruses can be.
Most monkeypox transmission is likely to occur by touch, according to Dr. Milton.
He said that the C.D.C. seemed to be stuck on the old terminology. We need to talk about transmission in terms that are clear about how it works.
Short-range airborne transmission is acknowledged by the C.D.C. Health care personnel caring for patients should wear N95 respirators, which are needed to filter out aerosols, as recommended by the agency.
Procedures that are likely to spread oral secretions should be done in an isolation room.
Monkeypox can live in aerosols and can cause disease in monkeys. It's possible that airborne transmission isn't the best way to transmit the monkeypox virus.
Dr. Marr said that patients may not release a lot of virus in aerosols, the virus may not remain infectious for long, or the amount of virus needed to spread may be too high.
People who are close for a long period of time are likely to be the ones who transmit airborne. In Britain and the United States, health officials say that many patients don't know when or where they've been exposed to the disease.
It's possible that airborne transmission has been occurring more than we know.