BACKGROUND AND OBJECTIVES: Many neonatal intensive care units (NICUs) do not give rotavirus vaccines to inpatients due to a theoretical risk of horizontal transmission of vaccine strains. We aimed to determine incidence and clinical significance of vaccine-strain transmission to unvaccinated infants in a NICU that routinely administers pentavalent rotavirus vaccine (RV5). METHODS: This prospective cohort study included all patients admitted to a 100-bed NICU for 1 year. Stool specimens were collected weekly; real-time quantitative reverse-transcription polymerase chain reaction was used to detect any RV5 strain. Incidence of transmission to unvaccinated infants was calculated assuming each unvaccinated patient's stool contributed 1 patient-day at risk for transmission. Investigations and geospatial analyses were conducted for suspected transmission events. RESULTS: Of 1238 infants admitted, 560 (45%) were premature and 322 (26%) had gastrointestinal pathology. During observation, 226 RV5 doses were administered. Overall, 3448 stool samples were tested, including 2252 from 686 unvaccinated patients. Most (681, 99.3%) unvaccinated patients never tested positive for RV5 strain. Five (<1%) tested RV5 strain positive. The estimated rate of transmission to unvaccinated infants was 5/2252 stools or 2.2/1000 patient-days at risk (95% CI: 0.7-5.2). No gastroenteritis symptoms were identified in transmission cases within 7 days of collection of RV5-positive stool. Of 126 patients for whom the RV5 series was initiated before the discharge date, 55% would have become age-ineligible to start the series if vaccination was allowed only at discharge. CONCLUSIONS: Transmission of RV5 strain was infrequent and without clinical consequences. Benefits of allowing vaccine-induced protection against rotavirus disease in infants through in-NICU RV5 vaccination appear to have outweighed risks from vaccine-strain transmission.

BACKGROUND: Rotavirus was the leading cause of acute gastroenteritis among US children until vaccine introduction in 2006, after which, substantial declines in severe rotavirus disease occurred. We evaluated rotavirus vaccine effectiveness (VE) over 13 years (2009-2022). METHODS: We analyzed data from the New Vaccine Surveillance Network using a test-negative case-control design to estimate rotavirus VE against laboratory-confirmed rotavirus infections among children seeking care for acute gastroenteritis (≥3 diarrhea or ≥1 vomiting episodes within 24 hours) in the emergency department (ED) or hospital. Case-patients and control-patients were children whose stool specimens tested rotavirus positive or negative, respectively, by enzyme immunoassay or polymerase chain reaction assays. VE was calculated as (1-adjusted odds ratio)×100%. Adjusted odds ratios were calculated by multivariable unconditional logistic regression. RESULTS: Among 16 188 enrolled children age 8 to 59 months, 1720 (11%) tested positive for rotavirus. Case-patients were less often vaccinated against rotavirus than control-patients (62% versus 88%). VE for receiving ≥1 dose against rotavirus-associated ED visits or hospitalization was 78% (95% confidence interval [CI] 75%-80%). Stratifying by a modified Vesikari Severity Score, VE was 59% (95% CI 49%-67%), 80% (95% CI 77%-83%), and 94% (95% CI 90%-97%) against mild, moderately severe, and very severe disease, respectively. Rotavirus vaccines conferred protection against common circulating genotypes (G1P[8], G2P[4], G3P[8], G9P[8], and G12[P8]). VE was higher in children <3 years (73% to 88%); protection decreased as age increased. CONCLUSIONS: Rotavirus vaccines remain highly effective in preventing ED visits and hospitalizations in US children.

The efforts of the Global Poliovirus Eradication Initiative (GPEI) have brought about the near elimination of poliovirus worldwide. The World Health Organization has issued guidelines for the safe handling and containment of infectious materials (IM) and potentially infectious materials (PIM) following poliovirus eradication. Inactivation of poliovirus in IM and PIM is needed to prevent inadvertent re-introduction of polioviruses post-eradication. In this study, we investigated the use of guanidine thiocyanate-based nucleic acid extraction buffers from commercially available nucleic acid extraction kits to inactivate poliovirus in cell culture isolates and stool suspensions, two common types of poliovirus IM and PIM, respectively. Incubation with selected nucleic acid extraction buffers or extraction buffers supplemented with ethanol reduced the infectivity of high-titer wild poliovirus type 1 (WPV1), wild poliovirus type 3 (WPV3), Sabin 1 (SL1), and Sabin 3 (SL3) cell culture isolates below the limit of detection in CCID(50) assays. Stool suspensions containing WPV1, WPV3, SL1, SL2, or SL3 were also inactivated by the extraction buffers tested. Blind passage of WPV1-spiked stool suspensions confirmed complete inactivation of WPV1 after incubation with extraction buffers. Moreover, treatment with a buffer consisting of 4 M guanidine thiocyanate with 30% ethanol inactivated a high-titer WPV1 culture isolate and a WPV1-spiked stool suspension. Taken together, these results show that guanidine thiocyanate-based nucleic acid extraction buffers are an effective means of inactivating poliovirus IM and PIM, and thus will be instrumental in ensuring containment compliance and preventing potential re-emergence of contained polioviruses.