The Risk of Intussusception After Rotavirus Vaccination
What is Rotavirus?
Rotavirus is a disease which causes severe diarrhea and vomiting, which can lead to severe dehydration, electrolyte imbalance, and death. It is the most common cause of gastroenteritis in children and infants worldwide and the effects can be devastating. Every year around the world, rotavirus causes the death of almost half a million children under five years old, due to the severe dehydration which results from the amount of diarrhea and vomiting the disease causes.
In countries with readily accessible healthcare, that number is much lower. However, even in the United States, unchecked rotavirus resulted in approximately 200,000 emergency room visits every year with as many as 60 children dying as a result. Washing hands, and general cleanliness helps, but the virus can still be transmitted and had a nearly 95% infection rate. No treatment for the virus itself exists. We can only the symptoms with rehydration therapy.
Finding a Vaccine
Researchers had been trying to discover a vaccine which would prevent rotavirus from causing such widespread infection. In 1998, a vaccine was made available on the market, but scientists discovered that it was associated with a rare, but potentially fatal, intestinal condition called intussusception. Intussusception happens in infants who had not been vaccinated, but there had been an increase in the rate among those who had received the 1998 vaccine. Therefore, the 1998 vaccine was removed from the market in 1999. Researchers were not able to discover a safe version of the rotavirus vaccine until 2006, called RotaTeq (a "pentavalent" vaccine), and another version of the vaccine, called Rotarix (a "monovalent" vaccine) was developed in 2008. Since 2008, in populations where the vaccine has been used, the rates of deaths caused by rotavirus have dropped by 40%. Clinical trials demonstrated that these vaccines were safe, but there was still a lingering question about whether intussusception is would be a risk from these new vaccines.
A number of studies have been undertaken since the advent of the new vaccines to determine whether the rates of post-vaccination intussusception are any higher than the "background" rate, or the rate of occurrence of that condition without a rotavirus vaccination. In 2014, a U.S. study published in the New England Journal of Medicine, showed that the monovalent vaccine, Rotarix, showed an increased risk of intussusception, though the pentavalent vaccine, RotaTeq did not. Furthermore, though the increased risk was present, it was very small (less than one hundredth of a percent increase over the background rate). In 2016, another study suggested that there was only a slight increased risk for children between 8 - 11 weeks, but no risk for children at other ages. In 2017, a German study of many different studies found an increased risk of intussusception if the child started the vaccine schedule after three months of age, as opposed to the recommended schedule in Germany beginning at 6-12 weeks old. However, another study of children in sub-Saharan Africa was published in the New England Journal of Medicine in 2018 which showed that no version of the vaccine given at any time created any increased risk of intussusception whatsoever. Because these studies seem to contradict each other, it is difficult to tell under what circumstances there might be an increased risk or even whether there is truly a risk at all. To make things even less clear, A 2009 study indicates that the United States may have been underestimating the "background" rates of intussusception by as much as 40%. That suggests that U.S. studies which show a risk of intussusception after vaccination which is higher than the "background" rate are wrong.
So, What is the Risk?
Some studies show no increased risk of intussusception after rotavirus vaccination. Some studies do show a small increase in risk, but we don't know if the results from the U.S. studies are reliable. However, in all the studies which have shown an increased risk, whether it is reliable or not, have only shown an extremely slight overall increase. What we do know is that before vaccination, rotavirus infected 95% of children between 3 months and 3 years old, resulted in 200,000 ER visits annually, and killed 60 children ever year. However, because there is a possible risk, the vaccine injury compensation program (the VICP) has made intussusception a "table injury." That means, that if your child develops intussusception after a rotavirus infection, you may be eligible for compensation. There are time limits, however, so you should contact an attorney experienced with the VICP, as soon as possible.