National vaccination strategy needed
“It is therefore expected that a national vaccination strategy, resulting in herd immunity, will be necessary to be able to offer infants with medical risks the necessary protection,” UMC Utrecht reported on Tuesday.
Research in healthy children is not always representative
Specific groups, such as children at high risk of serious intestinal infection due to rotavirus infection, such as preterm infants or those born with congenital abnormalities, are usually excluded from large-scale clinical studies. However, research in healthy children is not always representative of all children. It is therefore important to investigate whether a rotavirus vaccine also protects children with risk factors against vomiting and diarrhea caused by the rotavirus.
RIVAR
It is also relevant to investigate which vaccination strategy, target group-oriented or general, is the best option. Fien van Dongen (PhD student at the Julius Center for Health Sciences and Primary Care, UMC Utrecht) investigated in the Risk-group Infant Vaccination Against Rotavirus (RIVAR) study whether rotavirus vaccination is effective in infants with medical risks.
Insufficient protection
After follow-up from birth to 18 months in at-risk children from 13 Dutch hospitals participating in the RIVAR study, the efficacy of the vaccine was found to be only 30 percent (in 719 vaccinated infants). This contrasts with previous studies showing that vaccination was more than 80 percent effective in protecting against serious infections in healthy children.
National vaccination program
The vaccine appeared to be generally well tolerated by infants in the high-risk group, but the vaccination rate in this population was only 52.3 percent. Vaccinating only at-risk children therefore does not seem to be the right strategy for the prevention of rotavirus infection. The Health Council has therefore decided not to introduce rotavirus vaccination for this risk group. The most logical step would be a general vaccination of all infants through the National Immunization Programme, especially if the vaccine would become cheaper.
Group immunity
Fien van Dongen explains what vaccinating all children would entail: ‘We know from experiences in other countries that herd immunity can be achieved through a national vaccination strategy, which indirectly also protects children with medical risk factors. We believe that general vaccination against rotavirus can prevent a large proportion of rotavirus-associated hospitalizations and severe acute intestinal infection in children with risk factors as well as in healthy children.’
Underdeveloped immune system
About a possible explanation for the limited effect of the vaccine, she says: ‘It is probably a combination of factors. One of those factors is an immature immune system: in preterm infants, the immune response is generally less well developed. They therefore probably respond less well to this vaccine.
Average 28 days in hospital
In addition, many of these children – even if they are not premature – are seriously ill in the first weeks of life. They stay in the hospital for an average of 28 days after birth, with the necessary support for all kinds of vital functions, which can also have a disruptive effect on the immune system. And the first dose of the rotavirus vaccination should be given early in life, preferably between 6 and 9 weeks after birth.’
Rotavirus infection
Almost all children under the age of 5 contract the rotavirus. It is a contagious disease, in which an acute inflammation of the stomach and intestines occurs, leading to vomiting, diarrhea and fever. Although most children do not become very ill from it, tens of thousands of parents visit a doctor every year with their child due to an infection with the rotavirus.
Dehydration Symptoms
Every year in the Netherlands, an average of 3,600 children under the age of 5 are hospitalized with symptoms of dehydration as a result of the rotavirus, including many healthy children. Every year in the Netherlands 5 to 6 children die as a result of a rotavirus infection; these deaths usually occur in children with a medical risk factor. In its most recent advisory report (June 2021), the Health Council indicated that vaccination against rotavirus should be introduced in the National Immunization Program for all infants.
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