Rotavirus spreads by contact with infected faeces and might also be transmitted through faecally contaminated food, water and respiratory droplets.
The illness can begin abruptly with vomiting one to three days after infection, often before the onset of diarrhoea. The spectrum of illness ranges from mild, watery diarrhoea of limited duration to severe, dehydrating diarrhoea with vomiting, fever and shock. Symptoms generally resolve after three to seven days.
What vaccine is used against rotavirus?
Rotarix is the vaccine used for rotavirus in Australia. The vaccination course consists of two doses. The first dose should be given between 6 and 14weeks of age. The interval between the two doses should not be less than 4 weeks. The vaccine course should be completed by the age of 24 weeks as safety has not been assessed in older children.
Porcine Circovirus type 1 (PCV-1) material has been detected in ROTARIX vaccine. PCV-1 is not known to cause disease in animals and is not known to infect or cause disease in humans. There is no evidence that the presence of PCV-1 poses a safety risk.
How well does the vaccine work?
In 2017, NSW had the worst rotavirus outbreak in five years. The health department is exploring why the virus hit with such a vengeance this year, saying it may have mutated – making more people susceptible to infection. The effectiveness of a vaccine against the virus is also being investigated.
“Immunity from the vaccine wanes over several years, so that every few years there will be sufficient numbers of people who did not gain protection from the vaccine, or have lost protection, to allow an outbreak to occur,” a spokesman for NSW Health said in a statement”
Is the vaccine virus excreted in stools?
The weakened rotavirus from the vaccine may be found in stools for up to 28 days after the first immunisation and up to 15 days after the second dose.
Risk of intussusception
- There is new evidence from Australian and overseas studies suggesting a small increased risk of intussusception in infants following rotavirus vaccination.
- The increased risk appears to occur mainly in the first 1- 7 days following the first dose of rotavirus vaccine.
- Intussusception is rare, with an annual incidence under 12 months of age in Australia of 80 per 100,000, or about 200 cases per year. The increased risk would result in 2 additional cases of intussusception among every 100,000 infants vaccinated, or 6 additional cases per year in infants in Australia.
- It is also possible there may be a similar increased risk of intussusception after the second dose of rotavirus vaccine and that a smaller increased risk may continue for up to 21 days after vaccination.
- There is some indication that giving rotavirus vaccine later than the recommended upper age limits for each dose may increase the risk of intussusception.
What is intussusception?
Intussusception is a telescoping of one segment of the bowel into itself, causing obstruction. It is a rare condition, with an annual incidence under 12 months of age in Australia of 80 per 100,000, which represents approximately 200 cases per year. The peak incidence is between 5 and 10 months of age, with 80% of cases before 24 months of age. It is more common in males than females (5:3 in Australian studies). Most cases in infants are idiopathic, with no recognised triggering event or underlying structural abnormality. There may be some familial predisposition. Recurrence is seen in 5-10% of non-surgically-treated cases, usually within 6 months
How severe can intussusception get?
About 30% of infants with intussusception require surgical reduction and 10% result in intestinal resection. A recent review of state-wide cases conducted by the National Centre for Immunisation Research and Surveillance (NCIRS) for NSW Health found that, of 132 confirmed cases, 11% resolved spontaneously and 28% required surgery, with one infant admitted postoperatively to intensive care.
How will parents recognise if their baby develops intussusception?
It is recommended that parents seek medical advice if their baby develops intermittent crying/screaming episodes, start pulling their knees towards their chest, vomiting, or has pink or red coloured jelly-like stools