New monkeypox cases have declined by roughly 50% since August, Pfizer will supply millions of doses of Paxlovid to low-income countries to improve access to the treatment, and more in this week's roundup of monkeypox and Covid-19 news.

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Monkeypox:

• Since early August, the number of new monkeypox cases in the United States have declined by almost 50%, federal health officials report. According to CDC data, the seven-day average for new monkeypox cases peaked at 461 on Aug. 10, and it has since decreased to 170 cases as of Sept. 14. "We approach this news with cautious optimism," said CDC Director Rochelle Walensky, noting that some areas of the country are still seeing an increase in cases. "We continue to closely monitor data on this outbreak, those at risk, and how prevention measures are being used." As of Sept. 21, the United States has confirmed over 24,000 monkeypox cases. (Carbajal, Becker's Hospital Review, 9/19)

• Health care professionals (HCPs) who are exposed to patients with monkeypox are unlikely to be infected themselves, according to a new study published in CDC's Morbidity and Mortality Weekly Report. For the study, researchers from the Colorado Department of Public Health and Environment followed 313 HCPs who were exposed to 55 patients with monkeypox between May 1 and July 31. Of these workers, none contracted the virus over a 21-day follow up period, even though only 23% reported wearing all the PPE recommended by CDC when interacting with monkeypox patients. According to the researchers, although the health care workers in the study were not infected, "these results underscore the importance of public health outreach to better understand the circumstances of HCP exposures so that prevention, infection prevention education, and training of HCP can be improved, especially in primary care and urgent care settings." Recently, CDC released recommendations reiterating that health care workers should adhere to all recommended infection prevention and control measures, including wearing recommended PPE to reduce the risk of monkeypox transmission in health care settings. (Hein, MedPage Today, 9/16; AHA News, 9/16; AHA News, 9/19)

• CDC last week released new guidance recommending access to Tpoxx, an antiviral drug that is used to treat monkeypox, be limited to individuals who are at a high risk of severe disease. According to data recently released by FDA, widespread use of Tpoxx "could promote resistance and render the antivirals ineffective for some patients," CDC said. Currently, Tpoxx has been prescribed to tens of thousands of monkeypox patients, but it is only approved for the smallpox virus, and its use against monkeypox is still considered experimental. To determine Tpoxx's efficacy, NIH is conducting clinical trials in the United States and the Democratic Republic of the Congo. According to Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, NIH is currently recruiting both adult and child volunteers and hopes to have more than 500 U.S. participants. (Sun/Diamond, Washington Post, 9/15; Choi, The Hill, 9/15; Tin, CBS News, 9/14)

  Covid-19:

• Updated booster shots targeting the omicron subvariants could be authorized and available for children within a month, according to CDC. Currently, Pfizer-BioNTech is developing a bivalent vaccine for children ages 5 to 11, and Moderna is developing a similar vaccine for children ages 6 to 17. "If authorized by FDA, CDC anticipates a recommendation for bivalent COVID-19 vaccine as a booster for pediatric age groups in early to mid-October," CDC said. "It is expected that if bivalent boosters are authorized for individuals aged 5 years and older as a booster, monovalent mRNA COVID-19 vaccines may no longer be authorized as booster doses." So far, Pfizer-BioNTech's updated bivalent boosters have been authorized for individuals 12 and older and Moderna's have been authorized for adults ages 18 and older. (Bean, Becker's Hospital Review, 9/21)

• Pfizer on Thursday announced that it will supply up to 6 million courses of Paxlovid to the Global Fund to help improve access to Covid-19 oral treatments. According to the Global Fund, around 132 countries will be able to access Paxlovid based on their "income classification and disease burden." Eligible countries will be offered treatment courses based on Pfizer's tiered pricing approach that allows low- and lower-middle-income countries pay a not-for-profit price. "After so much disruption and loss due to COVID-19, we must continue to accelerate access to PAXLOVID as a safe and effective treatment option for high-risk patients in all regions of the world along with test and treat programs that help get treatment quickly to those in need," said Pfizer CEO Albert Bourla. (Habeshian, Axios, 9/22)

• Vaccine protection against hospitalization from the omicron BA.4/BA.5 subvariant declines rapidly, even after a third dose, according to a new study from South Africa published in the New England Journal of Medicine. For the study, researchers analyzed the health records of 32,883 South African patients in the Discovery Health insurance database. All participants had been hospitalized for medical treatment and tested for the coronavirus between Nov. 15, 2021, and June 24, 2022. In total, 5,909 (18%) of participants tested positive for the coronavirus. The researchers assessed the effectiveness of two or three vaccine doses against hospital admission to treat "possible sequelae" of Covid-19 using a test-negative design. Overall, the researchers found that the effectiveness of two doses of Pfizer-BioNTech's vaccine against hospitalization declined to 47.4% after three to four months and to 19.3% at nine months and later. In addition, protection against hospitalization from three doses declined to 68.8% after one to two months and 46.8% after three to four months. "Evidence of rapid waning of durability indicates the need for regular boosting as early as 4 months after the last dose or the need for vaccines to incorporate variants of concern to maintain protection," the researchers wrote. (Hein, MedPage Today, 9/15)