Efficacy and Safety of Available Rotavirus Vaccines

Kottapurath Kunjumoideen MD

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Acute diarrhea has been a major cause of death in young children worldwide until recently, and still true in many developing countries. The infectious agent for most of these diarrheas in young children is Rotavirus which was discovered in 1973 by Ruth Bisop. (Ref1). Rotavirus is shown to cause 40-50% of severe acute diarrhea in young children worldwide in both developing and developed countries. More than 600, 000 young children die every year from rotavirus disease, predominantly in South-East Asia and sub-Sahara. (Ref1).

Rotavirus is a double strand RNA virus belonging to the family of Reovirus. It is the most most common cause of diarrhea in infants and young children. Almost all kids have had a rotavirus infection by the time they're 5 years (Ref 2).

Wyeth introduced a Rotavirus vaccine (RotaShield) in1998. Clinical trials in US and many countries showed this to be highly effective vaccine. This vaccine was subsequently licensed for use in the United States. Wyeth, however, withdrew it from the market in 1999, after it was found that the vaccine may have contributed to an increased risk of bowel obstruction (Ref 4).

Subsequently two other vaccines (Rotarix by GlaxoSmithKline and RotaTeq by Merck) were introduced against Rotavirus. These were shown to be safe (Ref 5).

After the introduction of a rotavirus vaccine, a significant decline in diarrhea-related deaths was observed across many countries (Ref 6).

In recently published study in The Cochrane Library 2010, Issue 5 authored by Karla Soares-Weiser (Enhance Reviews Ltd, London, UK ) and colleagues , the authors studied three vaccines currently in use: Rotarix and which have been evaluated in several large trials and are approved for use in many countries; and Lanzhou Lamb Rotavirus vaccine (LLR), which is approved for use in China only (Ref 7). This study provides further evidence that Rotarix and RotaTeq are effective vaccines for the prevention of rotavirus diarrhea. They further conclude that even though there might be some risk to administration of these vaccines balance between benefit and harm favors the use of the vaccine. They further suggest that ongoing safety monitoring should be continued.

References:

1. Bishop R, Discovery of rotavirus: Implications for child health. J Gastroenterol Hepatol. 2009 Oct;24 Suppl 3:S81-5.
2. Dennehy PH (2000). "Transmission of rotavirus and other enteric pathogens in the home". Pediatr. Infect. Dis. J. 19 (10 Suppl): S103-5.
3. Richardson V, Hernandez-Pichardo J et. al. Effect of rotavirus vaccination on death from childhood diarrhea in Mexico. N Engl J Med. 2010 Jan 28;36 (4):299-305.
4. Bines J (2006). "Intussusception and rotavirus vaccines". Vaccine 24 (18): 3772-6.
5. Nakagomi T, Nakagomi O., A critical review on a globally-licensed, live, orally-administrable, monovalent human rotavirus vaccine: Rotarix. Expert Opin Biol Ther. 2009 Aug;9(8):1073-86.
6. Effect of rotavirus vaccination on death from childhood diarrhea in Mexico. Richardson V, Hernandez-Pichardo J, Quintanar-Solares M, Esparza-Aguilar M, Johnson B, Gomez-Altamirano CM, Parashar U, Patel M. N Engl J Med. 2010 Jan 28;362(4):299-305.
7. Soares-Weiser K, MacLehose H, Ben-Aharon I, Goldberg E, Pitan F, Cunliffe N Vaccines for preventing rotavirus diarrhoea: vaccines in use The Cochrane Library 2010, Issue 5 The Cochrane Library.