Impact of rotavirus vaccination on intussusception hospital admissions in England

Projected Public Health Impact of a Universal Rotavirus Vaccination Program in France

OBJECTIVE

In June 2022, French health authorities issued a universal recommendation for routine administration and reimbursement of rotavirus vaccines in infants. Given this recent recommendation by French health authorities, we sought to understand the public health impact of a universal rotavirus vaccination strategy compared with no vaccination.

MATERIALS AND METHODS

A deterministic, age-structured, nonlinear dynamic transmission model, accounting for herd immunity, was developed. We considered 3 vaccination coverage scenarios: high (95%), medium (75%) and low (55%). Model parameter values were based on published modeling and epidemiological literature. Model outcomes included rotavirus gastroenteritis (RVGE) cases and healthcare resource utilization due to RVGE (hospitalizations, general practitioner or emergency department visits), as well as the number needed to vaccinate to prevent 1 RVGE case (mild or severe) and 1 RVGE-related hospitalization. Model calibration and analyses were conducted using Mathematica 11.3.

RESULTS

Over 5 years following implementation, RVGE cases for children under 5 years are estimated to be reduced by 84% under a high vaccination coverage scenario, by 72% under a medium vaccination coverage scenario and by 47% under a low vaccination coverage scenario. Across all scenarios, the number needed to vaccinate to avert 1 RVGE case and hospitalization varied between 1.86-2.04 and 24.15-27.44, respectively.

CONCLUSIONS

Rotavirus vaccination with high vaccination coverage in France is expected to substantially reduce the number of RVGE cases and associated healthcare resource utilization.

Current Approaches in Postapproval Vaccine Safety Studies Using Real-World Data: A Systematic Review of Published Literature

PURPOSE

Well-designed observational postmarketing studies using real-world data (RWD) are critical in supporting an evidence base and bolstering public confidence in vaccine safety. This systematic review presents current research methodologies in vaccine safety research in postapproval settings, technological advancements contributing to research resources and capabilities, and their major strengths and limitations.

METHODS

A comprehensive search was conducted using PubMed to identify relevant articles published from January 1, 2019, to December 31, 2022. Eligible studies were summarized overall by study design and other study characteristics (eg, country, vaccine studied, types of data source, and study population). An in-depth review of select studies representative of conventional or new designs, analytical approaches, or data collection methods was conducted to summarize current methods in vaccine safety research.

FINDINGS

Out of 977 articles screened for inclusion, 135 were reviewed. The review shows that recent advancements in scientific methods, digital technology, and analytic approaches have significantly contributed to postapproval vaccine safety studies using RWD. "Near real-time surveillance" using large datasets (via collaborative or distributed databases) has been used to facilitate rapid signal detection that complements passive surveillance. There was increasing appreciation for self-controlled case-only designs (self-controlled case series and self-controlled risk interval) to assess acute-onset safety outcomes, artificial intelligence, and natural language processing to improve outcome accuracy and study timeliness and emerging artificial intelligence-based analysis to capture adverse events from social media platforms.

IMPLICATIONS

Continued development in the area of vaccine safety research methodologies using RWD is warranted. The future of successful vaccine safety research, especially evaluation of rare safety events, is likely to comprise digital technologies including linking RWD networks, machine learning, and advanced analytic methods to generate rapid and robust real-world safety information.

The Value of Rotavirus Vaccination in Europe: A Call for Action

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has pushed many healthcare systems into crisis. High vaccine coverage amongst children reduces emergency room presentations, hospital admissions and deaths due to vaccine-preventable diseases, freeing up healthcare resources including polymerase chain reaction testing for patients with SARS-CoV-2. In Europe, rotavirus gastroenteritis leads to 75,000-150,000 hospitalisations and up to 600,000 medical encounters annually. Nevertheless, in 2022, only 18 countries in Europe (out of 38) have a publicly funded routine universal mass immunisation programme against rotavirus gastroenteritis. Evidence available in the last few years re-emphasises that rotavirus vaccines currently available in Europe are highly effective, preventing up to 96% of rotavirus-related hospitalisations in children less than 1 year of age (potentially 72,000-144,000 hospitalisations Europe-wide). Long-term surveillance indicates that rotavirus vaccination does not result in an overall increase in intussusception. On the contrary, increasing evidence suggests an overall reduction in intussusception in the first 12 months of life when early, high rotavirus vaccine coverage is achieved. Prevention of rotavirus gastroenteritis has marked positive impacts on parental wages and government tax revenue, with benefits extending across the whole economy. In the SARS-CoV-2 pandemic setting there is a new imperative to achieve high levels of paediatric vaccination against vaccine-preventable diseases, including rotavirus gastroenteritis. The introduction of rotavirus universal mass vaccination can be expected to reduce the number of preventable illnesses, hospitalisations and deaths caused by rotavirus gastroenteritis. Reducing vaccine-preventable diseases is particularly urgent at this time when healthcare systems are preoccupied and overwhelmed with SARS-CoV-2. Graphical abstract available for this article.

Impact of polio vaccines (oral polio vaccine - OPV or inactivated polio vaccine - IPV) on rotavirus vaccine-associated intussusception

Although safe, rotavirus vaccines have been associated with increased intussusception risk. In Brazil, after the oral human rotavirus vaccine (OHRV) introduction in the childhood immunization, in 2006, increased intussusception risk was identified after the second OHRV dose, whereas in other countries, higher risk was associated to the first vaccine dose. It was hypothesized that the concomitant use of oral poliovirus vaccine (OPV) in Brazil might explain this difference. In 2012, the inactivated polio vaccine (IPV) was adopted in the first two doses of Brazilian childhood immunization schedule, creating an opportunity to study the subject. Our objective was analyzing the impact of polio vaccines on rotavirus-associated intussusception. We used surveillance data on intussusception in infants living in São Paulo State. Two periods were considered: an OPV-period (March 2006 to June 2012) and an IPV-period (October 2012 to December 2017). The period from June to September 2012 were considered as transition. Self-controlled case series analysis with event-dependent exposure was performed, considering two risk periods (7 and 21 days post-vaccination). We identified 325 intussusception cases in infants reported to the surveillance systems during the study period. The statistical analysis included 221 cases that occurred within 60 days after vaccination. Overall, a higher intussusception risk was observed in the first week after vaccination for both the first (Relative Incidence [RI] = 4.3, 95%CI 2.8-6.5, p < .001) and second vaccine doses (RI = 4.2, 95%CI 2.7-6.4; p < .001). There were no statistically significant differences in intussusception risk according to the rotavirus vaccine dose and the polio vaccine (OPV or IPV) administered concomitantly.

Impact of rotavirus vaccine in reducing hospitalization rates in pediatric patients: a single center experience in Italy

Rotavirus is a major cause of acute gastroenteritis in children under 5 years of age, with severe illness occurring in 30-40% of cases. In Italian region of Liguria, vaccination with a two-dose human attenuated vaccine was introduced in 2013. We conducted a retrospective study to assess the impact of rotavirus vaccine on hospitalizations for rotavirus-related gastroenteritis (RVGE) at the IRCCS Istituto Giannina Gaslini. Every hospitalization due to laboratory-confirmed RVGE and acute gastroenteritis of unknown origin (AGUO) in patients aged 0-14 years in the period 2008-2019 were anonymously extracted. Vaccine coverage were obtained from the regional vaccination registry. The results were divided in 2008-2012 (before RV vaccine) and 2013-2019 (after) periods. From 2008 to 2012, there was a continuous reduction of AGUO hospitalizations while RVGE increased. Since 2013, a reduction in hospitalization rate was observed for RVGE with a sharp decrease from 17.81 per 10.000 children in 2012 to 0.79 per 10,000 in 2019, parallel with the ascending values of RV vaccination coverage that increased from 36.3% in 2013 to 63.9% in 2019. A significant negative correlation was found between the proportions of vaccinated newborns and RVGE rates (p = .012). Intussusception-related hospitalization did not show substantial modifications. We confirm vaccination as a safe practice that has a significant impact in pediatric hospitalization rates.

Fourteen years' clinical experience and the first million babies protected with human live-attenuated vaccine against rotavirus disease in Italy

Rotavirus (RV) causes up to half of hospital and community acute gastroenteritis (AGE) cases in young children in Italy. Two RV vaccines, available since 2006, are human RV (HRV) and human bovine RV (HBRV). This report looks back at the implementation of RV vaccination with HRV in Italy, and at HRV current and future perspectives. Initial regional policies led to national implementation by 2018, after scientific societies' disease awareness efforts. Following vaccination, RV hospitalizations declined significantly, and cost savings were observed. The two-dose HRV vaccine is easily administered during compulsory vaccine visits, helping increase coverage. Intussusception, a serious event in children <1 year, was reported in Italy with a rate of 33-40 per 100,000 infants. RV vaccination presents a low increased risk of intussusception after the first dose, estimated at 0.6 cases per 100,000 doses in Italy in 2019. Parents should be aware of the intussusception risk and symptoms to ensure prompt treatment. It is widely recognized that the vaccination benefits (large numbers of RV hospitalizations prevented) outweigh the risk. HRV introduction in Italy was supported by epidemiologic burden studies, healthcare provider opinions, and congress debates, which significantly contributed to implementation of RV universal routine infant vaccination in Italy.

Safety of vaccines used for routine immunization in the United States: An updated systematic review and meta-analysis

BACKGROUND

Understanding the safety of vaccines is critical to inform decisions about vaccination. Our objective was to conduct a systematic review of the safety of vaccines recommended for children, adults, and pregnant women in the United States.

METHODS

We searched the literature in November 2020 to update a 2014 Agency for Healthcare Research and Quality review by integrating newly available data. Studies of vaccines that used a comparator and reported the presence or absence of key adverse events were eligible. Adhering to Evidence-based Practice Center methodology, we assessed the strength of evidence (SoE) for all evidence statements. The systematic review is registered in PROSPERO (CRD42020180089).

RESULTS

Of 56,603 reviewed citations, 338 studies reported in 518 publications met inclusion criteria. For children, SoE was high for no increased risk of autism following measles, mumps, and rubella (MMR) vaccine. SoE was high for increased risk of febrile seizures with MMR. There was no evidence of increased risk of  intussusception with rotavirus vaccine at the latest follow-up (moderate SoE), nor of diabetes (high SoE). There was no evidence of increased risk or insufficient evidence for key adverse events for newer vaccines such as 9-valent human papillomavirus and meningococcal B vaccines. For adults, there was no evidence of increased risk (varied SoE) or insufficient evidence for key adverse events for the new adjuvanted inactivated influenza vaccine and recombinant adjuvanted zoster vaccine. We found no evidence of increased risk (varied SoE) for key adverse events among pregnant women following tetanus, diphtheria, and acellular pertussis vaccine, including stillbirth (moderate SoE).

CONCLUSIONS

Across a large body of research we found few associations of vaccines and serious key adverse events; however, rare events are challenging to study. Any adverse events should be weighed against the protective benefits that vaccines provide.