(CNN) As the number of monkeypox cases climbs amid an ongoing global outbreak, US health officials said Friday that they are ramping up testing and contact tracing and expanding access to vaccines and treatments.
As part of those efforts, about 1,200 doses of vaccine for monkeypox have been offered in the United States, said Dr. Raj Panjabi, White House senior director for global health security and biodefense.
"We want to ensure that people with high-risk exposures have rapid access to vaccines and, if they become sick, can receive appropriate treatment. To date, we've delivered around 1,200 vaccines," Panjabi said. "And 100 treatment courses to eight jurisdictions, and we have more to offer states."
Health care workers in Massachusetts treating monkeypox patients were among the first to receive vaccinations to protect them against the virus.
In the United States, the two-dose Jynneos vaccine is licensed to prevent smallpox and specifically to prevent monkeypox. Another smallpox vaccine licensed in the United States, ACAM2000, can also be used for monkeypox.
To date, more than 120 PCR orthopox tests have been performed across the United States as part of monitoring the outbreak.
"This is just a fraction of what's available," Panjabi said, adding that 67 labs across 46 states -- part of a network known as the Laboratory Response Network -- have the "collective ability" to perform more than 1,000 tests per day.
"So what we're working on now is to ensure that that testing capacity is used," he said. People with monkeypox symptoms are encouraged to see a health care provider, and providers are urged to test if they suspect that someone might have monkeypox.
Officials with the US Centers for Disease Control and Prevention on Friday urged clinicians to be on the lookout for possible monkeypox cases as the virus could be spreading on the community level.
Twenty cases of monkeypox have been identified across 11 states, as well as an additional case in the United States who was infected and tested elsewhere, said Dr. Jennifer McQuiston, deputy director of the CDC's Division of High Consequence Pathogens and Pathology.
All of the patients are in recovery or have recovered, and those who still have a rash are being advised to stay home and isolate from others until they're fully recovered.
"I want to emphasize that this could be happening in other parts of the United States. There could be community-level transmission that is happening, and that's why we want to really increase our surveillance efforts," McQuiston said. "We want to really encourage physicians that if they see a rash and they're concerned it might be monkeypox, to go ahead and test for that."
She added that the rashes appearing as a result of monkeypox infections in this outbreak can be subtle and easily mistaken for other types of infections, especially sexually transmitted infections -- and there could be co-infections of monkeypox with STIs.
McQuiston said that the rash from a monkeypox infection typically appears as "deep-seated" and "well-rounded" lesions that progress to raised or fluid-filled pustules. It could be confused for other infectious diseases like herpes or syphilis, she added.
"That being said, we don't want to minimize this condition. The rash caused by monkeypox virus can spread widely across the body or present in sensitive areas like the genitalia," McQuiston said. "It can be really painful, and some patients have reported needing prescription pain medicine to manage that pain. The sores can also cause long-term scarring on the skin."
An analysis of genetic sequencing data from cases in the United States indicates that two genetically distinct variants of monkeypox may be circulating, McQuiston said.
The genetic sequence data is "certainly interesting from a scientific perspective," but "to determine how long monkeypox virus has been circulating is going to require analysis of a lot more sequences from a lot more patients to begin to piece together that puzzle in a clearer way," she said. "It's certainly possible that there could have been monkeypox cases in the United States that went under the radar previously, but not to any great degree."
She added that the risk to the public is still low and that the finding of cases with distinct lineages is a "positive sign" that the nation's surveillance network is working.
CDC researchers and health officials published a report Friday describing many of the US monkeypox cases, noting that "ongoing investigation suggests person-to-person community transmission, and CDC urges health departments, clinicians, and the public to remain vigilant, institute appropriate infection prevention and control measures, and notify public health authorities of suspected cases to reduce disease spread."
Among 17 cases described in the report across nine states, all of the patients had a rash, 14 of them reported traveling internationally during the 21 days preceding their symptoms, and all but one identified as a man who has sex with men (MSM). Three were immunocompromised. All of the patients were adults.
"The high proportion of initial cases diagnosed in this outbreak in persons who identify as gay, bisexual, or other MSM, might simply reflect an early introduction of monkeypox into interconnected social networks; this finding might also reflect ascertainment bias because of strong, established relationships between some MSM and clinical providers with robust STI services and broad knowledge of infectious diseases, including uncommon conditions," CDC researchers wrote in the report.
"However, infections are often not confined to certain geographies or population groups; because close physical contact with infected persons can spread monkeypox, any person, irrespective of gender or sexual orientation, can acquire and spread monkeypox."
Globally, officials at the World Health Organization say, more countries are reporting monkeypox cases that have not seen the virus before.
"Cases have been reported in 26 countries" where the virus is not endemic, Maria Van Kerkhove, WHO's emerging diseases and zoonoses lead and technical lead on Covid-19, said during a news briefing Thursday. She added that more than 600 cases have been identified in these countries.
"As surveillance increases, as attention increases, we expect that more cases will be identified," she said. "Many public health outbreak investigations are ongoing."
Rosamund Lewis, WHO's technical lead for monkeypox, said Tuesday that this outbreak is different from previous ones because "we're seeing cases all appearing in a relatively short period of time."
"What we're seeing now began as a small cluster of cases, and then the investigation rapidly led to discovery of infections in a group of men who have sex with men, and this led to further investigations, and so we don't yet know what the source of the actual outbreak is," Lewis said. "What's most important now is not to stigmatize."