Newswise — Philadelphia, December 9, 2024 – Researchers from found that transmission of rotavirus vaccine strains in a is rare and without clinical consequences, strongly suggesting that giving the rotavirus vaccine to eligible infants during their hospitalization provides immune benefits that outweigh any risks. The findings, published today in the journal Pediatrics, could serve as the basis for a change in clinical practice.
is a virus that infects the lining of the intestines and is typically characterized by symptoms such as high fever, persistent and severe vomiting and diarrhea. Before rotavirus vaccines were available, most children were infected before age 5, and the virus contributed to roughly half a million child deaths worldwide, and tens of thousands of hospitalizations of young children in the U.S., each year. Rotavirus remains the most common cause of diarrhea in infants and young children.
The first dose of a rotavirus vaccine is usually given to newborns at two months old. Historically, many NICUs do not give rotavirus vaccines to inpatients due to a theoretical risk of horizontal transmission of vaccine strains, meaning that the strains of the virus in the vaccine could potentially infect at-risk patients, since some vaccinated infants shed live, attenuated vaccine-strain rotavirus in their stool for weeks after administration. Holding vaccination until patients are discharged from the NICU often leaves infants with long hospitalizations, who are most vulnerable to severe rotavirus disease due to underlying health conditions, potentially making them ineligible to ever receive the vaccine. Prior retrospective studies found very minimal risk of horizontal transmission in NICU settings.
“As an infectious disease doctor who has worked on Infection Control in NICUs for many years, I was struck by how rarely vaccine virus was transmitted and how it did not cause clinical symptoms,” said co-senior study author , an attending physician for the at CHOP. “Our study, conducted in a large NICU with both multi-bed open pods and private rooms, adds to current evidence suggesting that risk of transmission of vaccine-strain rotavirus to unvaccinated infants in NICU settings is low.”
Bringing together expertise from across CHOP, including the Division of Infectious Diseases, the , the and , this study included all patients admitted to CHOP’s 100-bed N/IICU for one year. Stool specimens were collected weekly and tested to look for rotavirus vaccine strains. Investigations were conducted for suspected transmission events.
Among the 1238 infants admitted, 226 doses of the RotaTeq vaccine were administered. A total of 3448 stool samples were analyzed, including 2252 from 686 unvaccinated patients. The vast majority of those unvaccinated patients (681, or 99.3%) never tested positive for the rotavirus vaccine strain. The remaining five patients tested positive for a rotavirus vaccine strain. No gastroenteritis symptoms were identified in those transmission cases.
“While this study was conducted in a level 4 referral NICU, our combination of both single patient rooms as well as open pods supports its generalizability to a variety of NICUs of different layouts and sizes,” said , an attending neonatologist in the Division of Neonatology and Medical Director of Quality Improvement and Patient Safety of the NICU at CHOP. “Ultimately, these findings add to the existing safety data and suggest the known benefits of NICU administration of the rotavirus vaccine outweigh the low risks of vaccine-strain transmission.”
This study was supported by the Centers for Disease Control and Prevention grant 00HCVGEE-2020-43693.
Zalot et al, “Incidence of Transmission of Vaccine-Strain Rotavirus in a NICU that Routinely Vaccinates.” Pediatrics. Online December 9, 2024. DOI: 10.1542/2024-067621.
About Children’s Hospital of Philadelphia:
A non-profit, charitable organization, Children’s Hospital of Philadelphia was founded in 1855 as the nation’s first pediatric hospital. Through its long-standing commitment to providing exceptional patient care, training new generations of pediatric healthcare professionals, and pioneering major research initiatives, the hospital has fostered many discoveries that have benefited children worldwide. Its pediatric research program is among the largest in the country. The institution has a well-established history of providing advanced pediatric care close to home through its , which includes more than 50 primary care practices, specialty care and surgical centers, urgent care centers, and community hospital alliances throughout Pennsylvania and New Jersey, as well as and its dedicated pediatric emergency department in King of Prussia. In addition, its unique family-centered care and public service programs have brought Children’s Hospital of Philadelphia recognition as a leading advocate for children and adolescents. For more information, visit
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