Breakthrough cases of monkeypox may occur within two weeks of an initial vaccine dose, CDC will transition to weekly instead of daily Covid-19 case reports later this month, and more in this week's roundup of monkeypox and Covid-19 news.

Monkeypox:

• Most cases of breakthrough monkeypox occurred within two weeks of a first dose of the Jynneos vaccine, but some cases also occurred weeks after individuals had received their second dose, according to a new study that was published in JAMA. For the study, researchers analyzed 7,339 individuals who were vaccinated against monkeypox at Howard Brown Health in Chicago. In total, 400 people tested positive for monkeypox, with 90 cases occurring at least one day after vaccination. Of these breakthrough cases, 77% occurred within 14 days of the first dose, and 14% occurred within 14 to 28 days of the first dose. Among eight cases that occurred 28 days after initial vaccination, five occurred after a second dose. However, the researchers noted that "because the incubation period for monkeypox is 3 to 17 days, some of the cases occurring between 1 and 14 days after vaccination may not represent true vaccine failure" since "patients may have sought vaccination after realizing they were exposed." To ensure that people are maximally protected, health officials are encouraging eligible individuals to get a second vaccine dose as soon as possible. (Hein, MedPage Today, 10/5)

• According to a new CDC technical brief, monkeypox is unlikely to be completely eradicated from the United States in the near future, and experts predict that low-level transmission of the virus could continue indefinitely. "Our current assessment for the most likely longer-term scenario is that the outbreak will remain concentrated in [men who have sex with men], with cases slowing over the coming weeks, and falling significantly over the next several months," the report said. "We have moderate confidence in this assessment. We note that low-level transmission could continue indefinitely," but the total number of cases that may occur is still unclear. So far, increased vaccine availability, behavioral changes, and potentially growing immunity due to infection among those at the highest risk have helped the number of new monkeypox cases in the United States decline in recent weeks. (Carbajal, Becker's Hospital Review, 10/6)

• In a recent health advisory to its Health Alert Network, CDC warned health care workers to be alert for potentially severe cases of monkeypox in patients who are immunocompromised or co-infected with HIV. Clinicians are recommended to test all sexually active patients with monkeypox symptoms for HIV or other sexually transmitted infections, and early treatment with the antiviral drug tecovirimat (Tpoxx) should be considered for immunocompromised patients who have been infected. CDC recommended that clinicians optimize monkeypox treatment by limiting the use of immunosuppressive medications when "not otherwise clinically indicated" for immunocompromised patients and offering antiretroviral therapy for those with HIV. "Healthcare providers of people with monkeypox who are at risk for or who have severe manifestations of disease should reach out to their local public health jurisdictions or CDC for guidance about appropriate treatment," the agency wrote in the advisory. (AHA News, 9/30; Hein, MedPage Today, 9/30; CDC advisory, 9/29)

Covid-19:

• If 80% of eligible Americans receive an updated booster dose by the end of year, more than 936,000 hospitalizations and around 90,000 deaths from Covid-19 could be prevented, according to a new study from the Commonwealth Fund and the Yale School of Public Health. For the study, researchers used a simulation model to estimate the impact of vaccines in different scenarios. If vaccination rates for the updated boosters matched the levels of flu vaccination rates in 2020-2021 (50-55%), around 745,000 hospitalizations and 75,000 deaths from Covid-19 could be prevented. In a more ambitious scenario where 80% of eligible Americans receive a booster, over 936,000 hospitalizations and roughly 90,000 deaths could be prevented. This second scenario could also save the country $56.3 billion in direct medical costs, including $13.5 billion in Medicare spending and $4.5 billion in Medicaid spending. However, the United States is currently seeing much lower booster rates, with only 36% of adults ages 50 and older having received a dose, Axios reports. "If vaccination continued at its current pace through the end of March 2023, a potential winter surge in COVID-19 infections could result in a peak of around 16,000 hospitalizations and 1,200 deaths per day by March 2023," the researchers wrote. (Reed, Axios, 10/5; Fitzpatrick et al., The Commonwealth Fund, 10/5)

• Around 15% of U.S. adults currently report experiencing symptoms of long Covid, and more than 80% of this group say they have some trouble performing their daily activities, according to new data from CDC. The group with the highest rate of daily activity limitations was individuals ages 18 to 29, while the group with the lowest rate was those ages 40 to 49. When it came to the severity of their limitations, 25% of adults with long Covid said they said they had significant limitations on their day-to-day activities, a number that increased substantially among certain groups. While 20% of non-Hispanic white patients reported significant limitations in their activities, 37% of Hispanic or Latino and 38% of non-Hispanic Black patients reported the same. According to U.S. News & World Report, CDC's figures largely align with a previous report from the Brookings Institution, which estimated that up to 4 million adults are currently unable to work because of long Covid. "If long COVID patients don't begin recovering at greater rates, the economic burden will continue to rise," Brookings wrote. (Moreno, Axios, 10/6; Smith-Schoenwalder, U.S. News & World Report, 10/6)

• CDC on Thursday announced that it will transition to weekly reports on new Covid-19 cases instead of daily reports on Oct. 20. According to the agency, moving to weekly reports will allow for more "flexibility" and reduce the burden on local and state governments. "Data processing cutoffs for jurisdictions will be every Wednesday at 10AM ET for line level case and death data, and Wednesday at 5PM ET for aggregate case and death data," the CDC said. Similarly, the agency said it will no longer publish a list of Covid-19 travel advisories for countries outside of the United States, the New York Times reports. Going forward, CDC will issue travel health notices only if "a concerning Covid-19 variant" emerges or another situation changes travel recommendations for a specific country. (Choi, The Hill, 10/6; Cameron, New York Times, 10/3)