The rotavirus vaccine is effective in protecting children against the potentially deadly disease during the first year of life but may require a booster shot after infancy to maintain efficacy, says a new study published in the in the August 2012 issue of the journal Pediatrics.
According to the Centers for Disease Control and Prevention (CDC), rotavirus is caused by a virus that results in inflammation of the stomach and intestines. Symptoms of rotavirus include severe watery diarrhea, vomiting, fever, and abdominal pain. Without treatment, the diarrhea associated with rotavirus can lead to dehydration and even death, especially among young babies. Prior to the introduction of the rotavirus vaccine in 2006, rotavirus was the leading cause of death among infants. In developing countries where use of the rotavirus vaccine is still not widespread, rotavirus remains a deadly health problem.
In recent years, the rotavirus vaccine has come under attack because of a study published in the The Pediatric Infectious Disease Journal that concluded that the consumption of breast milk by babies during and shortly after administration of the oral rotavirus vaccine reduced the effectiveness of the vaccination. The authors of that study suggested that delaying breastfeeding to boost the efficacy of the rotavirus vaccine should be evaluated.
However, the results of that study were not applicable to infants living in developed countries who were receiving the oral rotavirus vaccine. In response to the findings of that study and the subsequent outcry of breastfeeding advocates, the president of the Academy of Breastfeeding Medicine (ABM) stated:
“Bottom line: the study has absolutely NO relevance to nursing mothers in industrialized countries ( surely NOT the US and Canada) and therefore NO change in the routines of breastfeeding infants who are being vaccinated are being suggested! (and so spread the word!)”
The present study also focused on the efficacy of the rotavirus vaccine in developing countries. Researchers at the CDC sought to evaluate the duration of protection offer by the rotavirus vaccine against hospitalization for the disease in the developing country of Nicaragua.
The rotavirus vaccine was added to the routine childhood immunization schedule in Nicaragua in October 2006. In order to determined the effectiveness of the vaccine, the researchers studied children in 4 hospitals between the years of 2007 and 2010. The participants included 1,016 children hospitalized with laboratory-conﬁrmed rotavirus diarrhea, 4,930 controls with non-rotavirus diarrhea, and 5,627 controls without diarrhea. All of the participants were six months old or older and were born after August 2006.
Effectiveness of the rotavirus vaccine during infancy was then then determined by comparing the effectiveness of the vaccine among participants who were less than a year old with the effectiveness of the vaccine among participants who were one year old or older.
According to the study, children vaccinated with the rotavirus vaccine were significantly less likely to be hospitalized for rotavirus diarrhea. However, protection against the disease declines with age. The risk of hospitalization for rotavirus was twofold lower among vaccination babies under the age of one compared with vaccinated children who were one year old or older.
The results of this study suggest that children may need a rotavirus vaccine booster after infancy in order to maintain the full effectiveness of vaccination against the rotavirus virus. As the researchers conclude:
“However, ongoing monitoring of rotavirus speciﬁc disease incidence in older groups will also be crucial, particularly for assessing the need for a potential booster dose of rotavirus vaccination at the end of the ﬁrst year of life (eg, concurrently with measles vaccination) in developing country settings. Clinical studies to assess the safety and noninterference of such a booster dose with measles vaccination, and whether it improves immune response sufﬁciently to provide sustained protection in developing countries should also be considered.”
Parents in developed countries such as the United States should not be alarmed by the results of this study. The researchers focused on the effectiveness of the rotavirus vaccine in Nicaragua, which is a low-middle income developing country in Central America. The results of this study are not necessarily applicable to babies living in middle- and upper-income developed countries.