Surveillance for Acute Flaccid Myelitis - United States, 2018-2022.

Acute flaccid myelitis (AFM) is a serious neurologic condition primarily affecting children; AFM can cause acute respiratory failure and permanent paralysis. AFM is a rare but known complication of various viral infections, particularly those of enteroviruses (EVs). Increases in AFM cases during 2014, 2016, and 2018 were associated with EV-D68 infection. This report examines trends in confirmed AFM cases during 2018-2022 and patients' clinical and laboratory characteristics. The number of AFM cases was low during 2019-2022 (28-47 cases per year); the number of cases remained low in 2022 despite evidence of increased EV-D68 circulation in the United States. Compared with cases during the most recent peak year (2018), fewer cases during 2019-2021 had upper limb involvement, prodromal respiratory or febrile illness, or cerebrospinal fluid pleocytosis, and more were associated with lower limb involvement. It is unclear why EV-D68 circulation in 2022 was not associated with an increase in AFM cases or when the next increase in AFM cases will occur. Nonetheless, clinicians should continue to suspect AFM in any child with acute flaccid limb weakness, especially those with a recent respiratory or febrile illness.

National Surveillance for Acute Flaccid Myelitis - United States, 2018-2020.

Acute flaccid myelitis (AFM), a recognized complication of certain viral infections, is a serious neurologic condition that predominantly affects previously healthy children and can progress rapidly, leading to respiratory insufficiency and permanent paralysis. After national AFM surveillance began in 2014, peaks in AFM cases were observed in the United States in 2014, 2016, and 2018 (1). On the basis of this biennial pattern, an increase in AFM was anticipated in 2020. To describe the epidemiology of confirmed AFM cases since 2018, demographic, clinical, and laboratory information collected as part of national AFM surveillance was reviewed. In 2018, a total of 238 confirmed AFM cases were reported to CDC, compared with 47 cases in 2019 and 32 in 2020. Enterovirus D68 (EV-D68) was detected in specimens from 37 cases reported in 2018, one case in 2019 and none in 2020. Compared with 2018, cases reported during 2019-2020 occurred in older children and were less frequently associated with upper limb involvement, febrile or respiratory prodromal illness, or cerebrospinal fluid (CSF) pleocytosis. These findings suggest that the etiologies of AFM in 2019 and 2020 differed from those in 2018. The absence of an increase in cases in 2020 reflects a deviation from the previously observed biennial pattern, and it is unclear when the next increase in AFM should be expected. Clinicians should continue to maintain vigilance and suspect AFM in any child with acute flaccid limb weakness, particularly in the setting of recent febrile or respiratory illness.

Evaluation of Intussusception after Monovalent Rotavirus Vaccination in Africa.

BACKGROUND: Postlicensure evaluations have identified an association between rotavirus vaccination and intussusception in several high- and middle-income countries. We assessed the association between monovalent human rotavirus vaccine and intussusception in lower-income sub-Saharan African countries. METHODS: Using active surveillance, we enrolled patients from seven countries (Ethiopia, Ghana, Kenya, Malawi, Tanzania, Zambia, and Zimbabwe) who had intussusception that met international (Brighton Collaboration level 1) criteria. Rotavirus vaccination status was confirmed by review of the vaccine card or clinic records. The risk of intussusception within 1 to 7 days and 8 to 21 days after vaccination among infants 28 to 245 days of age was assessed by means of the self-controlled case-series method. RESULTS: Data on 717 infants who had intussusception and confirmed vaccination status were analyzed. One case occurred in the 1 to 7 days after dose 1, and 6 cases occurred in the 8 to 21 days after dose 1. Five cases and 16 cases occurred in the 1 to 7 days and 8 to 21 days, respectively, after dose 2. The risk of intussusception in the 1 to 7 days after dose 1 was not higher than the background risk of intussusception (relative incidence [i.e., the incidence during the risk window vs. all other times], 0.25; 95% confidence interval [CI], <0.001 to 1.16); findings were similar for the 1 to 7 days after dose 2 (relative incidence, 0.76; 95% CI, 0.16 to 1.87). In addition, the risk of intussusception in the 8 to 21 days or 1 to 21 days after either dose was not found to be higher than the background risk. CONCLUSIONS: The risk of intussusception after administration of monovalent human rotavirus vaccine was not higher than the background risk of intussusception in seven lower-income sub-Saharan African countries. (Funded by the GAVI Alliance through the CDC Foundation.).

Rotavirus Vaccines and Health Care Utilization for Diarrhea in US Children, 2001 to 2015.

BACKGROUND: Rotavirus vaccination was introduced in the United States in 2006. Our objectives were to examine reductions in diarrhea-associated health care utilization after rotavirus vaccine implementation and to assess direct vaccine effectiveness (VE) in US children. METHODS: Retrospective cohort study using claims data of US children under 5 years of age. We compared rates of diarrhea-associated health care utilization in prevaccine versus postvaccine introduction years. We also examined VE and duration of protection. RESULTS: Compared with the average rate of rotavirus-coded hospitalizations in the prevaccine years, overall vaccine rates were reduced by 75% in 2007 to 2008, 60% in 2008 to 2009, 94% in 2009 to 2010, 80% in 2010 to 2011, 97% in 2011 to 2012, 88% in 2012 to 2013, 98% in 2013 to 2014 and 92% in 2014 to 2015. RotaTeq-adjusted VE was 88% against rotavirus-coded hospitalization among 3-11 months of age, 88% in 12-23 months of age, 87% in 24-35 months of age, 87% in 36-47 months of age and 87% in 48-59 months of age. Rotarix-adjusted VE was 87% against rotavirus-coded hospitalization among 3-11 months of age, 86% in 12-23 months of age and 86% in 24-35 months of age. CONCLUSION: Implementation of rotavirus vaccines has substantially reduced diarrhea-associated health care utilization in US children under 5 years of age. Both vaccines provided good and enduring protection through the fourth year of life against rotavirus hospitalizations.