17 Rotavirus

17.3 Epidemiology

17.3.1 Global burden of disease

Rotavirus gastroenteritis is a significant cause of infant diarrhoea worldwide, both in developed and developing countries. Virtually all children are infected by age 5 years.1 Each year rotavirus causes the death of approximately 200,000 to 450,000 children aged under 5 years worldwide8, 9 and results in 2.4 million paediatric hospital admissions.10 Virtually all of the deaths occur in developing countries. Prior to the introduction of licensed rotavirus vaccines in developed countries, more than 220,000 children were hospitalised with rotavirus gastroenteritis every year.11, 12

Rates of rotavirus illness in children in developed and developing countries are similar, indicating that good hygiene and clean water supplies are unlikely to have a significant impact on disease prevention. As a result, immunisation is the primary public health measure for the reduction of rotavirus disease burden.1

In countries with a temperate climate, rotavirus epidemics occur every winter and spring. Factors associated with an increased risk of severe rotavirus gastroenteritis include age under 2 years, low birthweight, premature gestation, lack of breastfeeding, socioeconomic disadvantage, malnutrition and impaired immunity.1, 13–16 Rotavirus gastroenteritis is not, however, more severe in HIV-infected children, although viral shedding may be longer.2

Rotavirus is an important cause of hospital-acquired infection17 and can also cause disease in adults, especially those caring for children18 and those living in aged-care facilities. During outbreaks in early childhood settings, rotavirus has been isolated from telephone receivers, drinking fountains, water-play tables and toilet handles.19 Outbreaks in elderly populations may be linked to waning immunity, institutional crowding or both.

Children and adults can be infected with rotavirus several times in their lives. After a single natural infection during infancy, approximately one third are protected against subsequent rotavirus infection, and more than three-quarters are protected against subsequent rotavirus gastroenteritis and 85–90 percent against severe rotavirus gastroenteritis.20 The proportion with protection against both infection and symptomatic rotavirus gastroenteritis increases with successive episodes.20

These observations serve as the biological basis for rotavirus vaccines, whereby live attenuated strains are capable of inducing cumulative protective immunity similar to that following natural infection by wild-type rotaviruses. Although the immune mechanism and correlates of protection against rotavirus infection and gastroenteritis are incompletely understood, it is likely that both mucosal and serum antibodies are associated with protection against rotavirus infection and disease.21

17.3.2 New Zealand epidemiologyTop

At present rotavirus is not a notifiable disease, so there is no national surveillance data available. Data estimates of the burden of disease predict that by the age of 5 years, 1 in 5 children will have sought medical advice for rotavirus gastroenteritis and 1 in 43 children will be hospitalised.11

Data was collected prospectively on children aged under 3 years with acute diarrhoea who were admitted to eight hospitals in New Zealand from 1 May 1998 to 30 April 2000. The estimated national hospitalisation rate for rotavirus diarrhoea in children aged under 3 years, standardised for age and season, was 634 per 100,000 (95% CI: 597–672).22

Of the 2019 hospitalised children enrolled in the study, 1138 had stools available for testing, of which 485 (42.5 percent) tested rotavirus positive. Rotavirus detection in stool samples varied significantly by age (27 percent of stool samples from infants aged 0 to 5 months, 43 percent from children aged 6 to 11 months, and 52 percent from children aged 12 to 35 months; p < 0.001). A winter peak was apparent, with rotavirus detected in 51 percent of the samples collected during winter/spring compared with 25 percent during summer/autumn (p < 0.001).22