Infectious Disease Updates
September 1, 2025
By Carol A. Kemper, MD, FIDSA
Eradication of Polio Around the World
Source: Namageyo-Funa A, Greene SA, Henderson E, et al. Update on vaccine-derived Poliovirus outbreaks — Worldwide, January 2023-June 2024. MMWR Morb Mortal Wkly Rep. 2024;73:909-916.
The Global Polio Eradication Initiative (GPEI) of 2022-2026 aimed to eradicate all cases of vaccine-derived polio in 2024. Since 2022 there have been no reports of new outbreaks of circulating vaccine-derived poliovirus 1 (cVDPV1), and cases of cVDPV2 have marginally decreased in affected countries. Despite introduction of a novel, more genetically stable type 2 oral polio vaccine (OPV), its broader use has been hampered by manufacturing delays, problems with distribution in war-torn countries, and the after effects of the COVID-19 outbreak, which resulted in a larger number of undervaccinated children in many African countries.
Since 2015, the strategy has been to stop the use of trivalent OPV (which contains Sabin type 1, 2, and 3 strains) and instead use the bivalent OPV (containing Sabin type 1 and 3 strains) in countries with cVDPV1 outbreaks, and the monovalent type 2 OPV for countries with cVDPV2 outbreaks. Cases are verified and tabulated by serogroup, source, and area.
Despite these changes, new cVDPV2 outbreaks continue to occur, especially in Africa. From January 2023 to June 2024, 74 outbreaks were detected in 39 countries (mostly in Africa), including 47 new outbreaks in 30 countries and 27 earlier outbreaks and were ongoing.1 This includes 38 countries with cVDPV2 outbreaks, one country with an ongoing cVDPV1 outbreak, and two countries (Democratic Republic of Congo and Mozambique) with outbreaks caused by both strains. These outbreaks resulted in 672 new cases of acute flaccid paralysis from 27 countries. The remaining 12 countries reported cVDPV outbreaks through environmental surveillance and sampling healthy individuals in the community. Prolonged outbreaks (> 1 year) occurred in 15 countries (12 African countries, as well as Madagascar, Yemen, and Indonesia). Ongoing outbreaks of cVDPV2 infection in Nigeria and Somalia have spread to adjacent countries.
The updated 2024-2025 plan for Africa is to eradicate all new cases of cVDPV1 by December 2024 (which thus far seems successful) and to stop all new cases of cVDPV2 by December 2025. Supplemental vaccine action has been undertaken in 32 of the 39 countries mentioned earlier, and this plan appear to be zeroing in on its goal. As of June 2025, the World Health Organization (WHO) reports no new cases of cVDPV1 or positive environmental samples for 2025; and the Madagascar cVDPV1 outbreak was successfully contained in 2024.2 Cases and positive environmental samples for cVDPV2 continue to occur, although at a reduced rate — only 67 cases and 69 environmental samples of cVDPV2 have been reported thus far for 2025. Remarkably, two of 15 outbreaks identified in 2025 are new and due to the novel OPV2 vaccine, although it still is believed that vaccine has a lower risk of reversion to neurovirulence.
There still is an upward trend in environmental samples showing wild polio virus 1 in core reservoir areas in Pakistan and Afghanistan, and nine new cases of wild polio virus 1 occurred in these countries in 2025, posing a risk to the global plan to eradicate polio.
References
1. Namageyo-Funa A, Greene SA, Hendeson E, et al. Update on vaccine-derived poliovirus outbreaks – Worldwide, January 2023-June 2024. MMWR Morb Mortal Wkly Rep. 2024;73:909-916.
2. World Health Organization. Statement of the forty-second meeting of the polio IHR Emergency Committee. July 28, 2025. https://www.who.int/news/item/28-07-2025-statement-of-the-forty-second-meeting-of-the-polio-ihr-emergency-committee
Candida auris in Dialysis Facilities: How Great Is the Risk?
Source: Kurutz A, Innes GK, Sherman A, et al. Candida auris containment responses in health care facilities that provide hemodialysis services — New Jersey, North Carolina, South Carolina, and Tennessee, 2020-2023. MMWR Morb Mortal Wkly Rep. 2025;74:415-421.
In 2023-2024, the Centers for Disease Control and Prevention (CDC) was made aware of six patients with Candida auris receiving dialysis services at five different facilities in four states from 2020-2023. The average age of the patients was 64 years (range, 38-79 years). Three patients were colonized with C. auris and three were clinical cases with infection of urine, wound, or blood. They each received dialysis for four months or less following their positive C. auris test result. Because the dialysis facilities were unaware of this information, standard dialysis infection prevention precautions were used.
Once this information was recognized, an investigation was launched, examining any other facilities the six index cases had been located in. Screening cultures were recommended for any patients previously residing on the same floor of another facility at the same time as the index patient, and for any person receiving dialysis on the same day or the following day as the index case. Each state conducted at least one round of colonization testing. Screening procedures varied by state, but generally test samples were collected from the axilla, groin, or nares using a flocked Eswab and processed by polymerase chain reaction at their state laboratory facility.
A total of 174 potential contacts were screened, revealing only one positive individual. That individual turned out to be a known positive for C. auris four months earlier — unbeknownst to the investigators. No other positives were identified.
C. auris is an environmental pathogen, and has the potential to colonize surfaces in facilities, including tray tables and the windowsill in a hospital room. As such, it could pose a risk within facilities for broader colonization of persons entering the facility. Dialysis patients represent a unique and vulnerable patient population, being generally unhealthy, but also requiring invasive procedures and regular vascular access. While most patients remain colonized, fatality rates may be as high as 40% in those who develop active infection.
The question remains: What precautions are necessary to contain the spread of this organism within dialysis units? This study suggests the rate of transmission to other patients when using standard precautions alone in dialysis facilities was low. However, relatively few people were screened in this study (~34 people per dialysis site), they were screened months to years following potential exposure, screening techniques varied, and only one to three skin sites were tested. No mention was made of an attempt to track patients who were no longer available for screening or who had died.
A 2021 study examining the sensitivity of testing for C. auris body site colonization found that swabs of the anterior nares had the lowest sensitivity of detection (< 60%), and that 30% to 40% of patients with C. auris were colonized in the axilla or groin.1 Swabbing six sites was necessary for 100% sensitivity with screening. Thus, it is conceivable this investigation missed other possible cases. Further, no mention was made of an attempt to review the histories of patients who were no longer available for screening or who had died. Since this is an environmental pathogen, which easily colonizes equipment and surfaces and causes skin colonization, it seems the risk for transmission between dialysis patients could easily be greater than 0.6%.
In April 2024, the CDC issued general guidance for C. auris in facilities, specifying standard precautions, with the proviso that “setting-based precautions” should be used.2 They also recommended that equipment used for such patients, such as blood pressure cuffs and carts, be labeled and kept separate for specific cleaning. Cleaning products must be effective for C. auris (not quaternary ammonia products). Required notification to facilities providing care to such patients is an essential first step.
Carol A. Kemper, MD, FIDSA, is Medical Director, Infection Prevention, El Camino Hospital, Palo Alto Medical Foundation.
References
1. Proctor DM, Dangana T, Sexton DJ, et al. Integrated genomic, epidemiologic investigation of Candida auris skin colonization in a skilled nursing facility. Nature Med. 2021;27:1401-1409.
2. Centers for Disease Control and Prevention. Infection Control Guidance: Candida auris. April 24, 2024. https://www.cdc.gov/candida-auris/hcp/infection-control/index.html
Eradication of Polio Around the World; Candida auris in Dialysis Facilities: How Great Is the Risk?
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