Evaluation of Intussusception Following Pentavalent Rotavirus Vaccine (RotaTeq) Administration in 5 African Countries

Australia's rotavirus immunisation program: Impact on acute gastroenteritis and intussusception hospitalisations over 13 years

BACKGROUND

Australia was one of the first countries to include rotavirus vaccines in its National Immunisation Program, in 2007. We compared trends in acute gastroenteritis (AGE) and intussusception-coded hospitalisations over 13-year post-vaccine period against five-year pre-vaccine baseline.

METHODS

In a descriptive before-after study, incidence of hospitalisations with ICD-code of rotavirus AGE (A08.0), other AGE (K52, A01-A09 excluding A08.0) or intussusception (K56.1) between 2002 and 2020 was calculated using population denominators by age and Indigenous status. We used 2002-2006 as pre-vaccine baseline and calculated Incidence Rate Ratios [IRRs] for 2008-2019 and 2020.

FINDINGS

In children aged <5 years, mean annual hospitalisation rate/100,000 decreased by 85% for rotavirus-coded AGE, from 248.3 in 2002-2006 to 37.6 (IRR 0.15; 95% CI 0.15-0.16) in 2008-2019 (61.4% for Indigenous children, from 680.2 to 262.2), and 46% for other AGE, from 1274.5 to 689.1 (IRR 0.54; CI 0.54-0.55), decreasing further in 2020 to 6.3 (rotavirus-coded) and 445.0 (other AGE). Rates for rotavirus-coded and other AGE declined in 2008-2019 in those aged 5-<20 years (IRR 0.52; CI 0.49-0.56 and 0.86; CI 0.85-0.87, respectively), but increased in 20-<65 years (IRR 2.38; CI 2.01-2.83 and 1.15; CI 1.15-1.16) and ≥65 years (IRR 2.24; CI 1.91-2.62 and 1.24; CI 1.23-1.25). Average annual hospitalisation rate for intussusception in infants was similar in pre-vaccine and post-vaccine periods (IRR 0.97; CI 0.90-1.04).

CONCLUSION

Over a 13-year period post-rotavirus vaccine introduction we document major sustained declines in hospitalisations coded as rotavirus and other AGE in age groups <20 years, with no change in intussusception hospitalisation rates in infants. Despite small increases in AGE hospitalisations in adults, likely due to increased PCR testing, our findings are consistent with highly favourable risk benefit ratio at whole-of-population level in Australia.

Challenges and lessons learned during the switching of rotavirus vaccine from Rotarix to Rotavac in Zambia

INTRODUCTION

Active Rotavirus diarrhea surveillance has been ongoing in Zambia at three dedicated sentinel sites since 2007, focusing on hospitalized children under five years of age. During 2021 and 2022, many African countries, including Zambia, experienced a severe shortage of rotavirus vaccines. This vaccine shortage resulted in many children who were eligible for vaccination remaining unvaccinated. Consequently, these children were exposed to a higher risk of severe acute gastroenteritis.

METHODS

To ascertain the impact of rotavirus vaccine stock-out and switch in Zambia, a comprehensive desk review was conducted focusing on the switch of the vaccine from Rotarix to Rotavac and the change of the Rotavac formulation. This review encompassed all children under five years of age recruited at the surveillance sites between 2017 and 2023 and the country's comparison of national administrative and WUENIC 2023 rotavirus vaccine coverage rate estimates for 2014 to 2023. March 2022 to April 2023 was defined as the Rotarix vaccine stock-out period. Hospitalization trends, demographic and clinical data, and rotavirus confirmed ELISA results were analyzed.

RESULTS

Following the introduction of rotavirus vaccine, the number of fully vaccinated children increased steadily over the years, reaching 4.73 million in 2023. However, 2.63 million children missed vaccination between 2016 and 2023. The administrative and WUENIC 2023 estimates for rotavirus coverage rates were the same during the period under review. Hospitalized diarrhea cases and rotavirus positivity rates remained essentially the same during the in-stock and stock-out periods of rotavirus vaccine. However, mortality rates increased three-fold during the vaccine stock-out period.

CONCLUSION

The impact of the Rotarix vaccine era was reversed due to the global supply chain disruptions, leading to missed vaccinations, increased diarrhea-related hospitalizations, and higher infant mortality in Zambia. The COVID-19 pandemic may also have further disrupted the vaccination sessions, further impacting rotavirus vaccination. Rotarix shortages likely contributed to rising rotavirus cases. There is an urgent need to completely replace the old under-5 vaccination card with a revised one to improve documentation for new rotavirus vaccines.

Intussusception and Other Adverse Event Surveillance after Pilot Introduction of Rotavirus Vaccine in Nam Dinh and Thua Thien Hue Provinces-Vietnam, 2017-2021

Rotavin-M1 (POLYVAC) was licensed in Vietnam in 2012. The association of Rotavin-M1 with intussusception, a rare adverse event associated with rotavirus vaccines, and with adverse events following immunization (AEFI) have not been evaluated and monitored under conditions of routine use. From February 2017 to May 2021, we conducted a pilot introduction of Rotavin-M1 into the routine vaccination program in two provinces. Surveillance for intussusception was conducted at six sentinel hospitals. AEFI reports at 30 min and 7 days after vaccination were recorded. Among 443 children <12 months of age admitted for intussusception, most (92.3%) were children ≥ 6 months. Of the 388 children who were age-eligible to receive Rotavin-M1, 116 (29.9%) had received ≥1 dose. No intussusception cases occurred in the 1-21 days after dose 1 and one case occurred on day 21 after dose 2. Among the 45,367 children who received ≥1 dose of Rotavin-M1, 9.5% of children reported at least one AEFI after dose 1 and 7.3% after dose 2. Significantly higher AEFI rates occurred among children given Rotavin-M1 with pentavalent vaccines (Quinvaxem®, ComBE Five®) compared to Rotavin-M1 without pentavalent vaccines. There was no association between intussusception and Rotavin-M1. The vaccine was generally safe when administered alone and when co-administered with other vaccines.

Intussusception risk following oral monovalent rotavirus vaccination in 3 Asian countries: A self-control case series evaluation

Rotavirus vaccines have substantially decreased rotavirus hospitalizations in countries where they have been implemented. In some high- and middle-income countries, a low-level of increased risk of intussusception, a type of acute bowel obstruction, has been detected following rotavirus vaccination. However, no increased risk of intussusception was found in India, South Africa, or a network of 7 other African countries. We assessed the association between a 2-dose monovalent rotavirus vaccine (Rotarix) and intussusception in 3 early-adopter low-income Asian countries -- Afghanistan, Myanmar, and Pakistan. Children <12 months of age admitted to a sentinel surveillance hospital with Brighton level 1 intussusception were eligible for enrollment. We collected information about each child's vaccination status and used the self-controlled case series method to calculate the relative incidence of intussusception 1-7 days, 8-21 days, and 1-21 days following each dose of vaccine and derived confidence intervals with bootstrapping. Of the 585 children meeting the analytic criteria, the median age at intussusception symptom onset was 24 weeks (IQR: 19-29). Overall, 494 (84 %) children received the first Rotarix dose and 398 (68 %) received the second dose. There was no increased intussusception risk during any of the risk periods following the first (1-7 days: 1.01 (95 %CI: 0.39, 2.60); 8-21 days: 1.37 (95 %CI: 0.81, 2.32); 1-21 days: 1.28 (95 %CI: 0.78, 2.11)) or second (1-7 days: 0.81 (95 %CI: 0.42, 1.54); 8-21 days: 0.77 (95 %CI: 0.53, 1.16); 1-21 days: 0.78 (95 %CI: 0.53, 1.16)) rotavirus vaccine dose. Our findings are consistent with other data showing no increased intussusception risk with rotavirus vaccination in low-income countries and add to the growing body of evidence demonstrating safety of rotavirus vaccines.