Update on Rotarix™: an oral human rotavirus vaccine

Abstract

Worldwide, rotaviruses are the single most important agents of severe gastroenteritis in infants and young children. Globally, it is estimated that every year rotavirus gastroenteritis causes more than 125 million episodes of diarrhea and nearly 527,000 deaths, mainly in developing countries. The development of new effective and safe rotavirus vaccines was recognized as the most effective intervention strategy that could yield a significant impact on the burden of rotavirus disease. Rotarix™ is an oral live-attenuated human rotavirus vaccine containing a single G1P[8] strain. The first oral dose may be administered as early as 6 weeks of age, with a minimum interval of 4 weeks prior to second dose; the vaccination course should be completed by the age of 24 weeks according to the manufacturer. In the USA, the upper age limit for the second dose has recently been recommended at 32 weeks of age by the Advisory Committee on Immunization Practices. The development program for Rotarix including Phase I, II and III multicenter studies involving over 100,000 infants has been established in Latin America, Europe, Asia and Africa. The vaccine proved to be well tolerated, immunogenic, efficacious, safe and not associated with intussusception. It provided 85–96% protection against severe rotavirus gastroenteritis caused by G1 and non-G1 serotypes in Latin American and European clinical trials; and of public health importance, Rotarix reduced hospitalizations of all-cause gastroenteritis by 40 and 75%, respectively. Efficacy against G2P[4] strains ranged from 41% in Latin America to 81% in Europe. In the former, Rotarix afforded sustained high protection (80.5%; 95% CI: 71.3–87.1) against severe rotavirus gastroenteritis during the first 2 years of life in a region with a changing pattern of wild-type rotavirus circulation. In a recently completed vaccine trial in South Africa and Malawi, Rotarix showed an overall efficacy of 61.2% (95% CI: 44.0–73.2) by 1 year of age. Although these rates are lower than those from developed and middle-income countries, they look promising given the lack of other effective interventions. With the expanding introduction of rotavirus vaccines into national immunization programs, postmarketing surveillance should be conducted to measure the impact of rotavirus vaccination, as well as continued monitoring of circulating rotavirus strains.

Keywords::

• dehydration
• diarrhea
• gastroenteritis
• human-attenuated
• immunity
• prevention
• rotavirus
• serotype
• vaccine
• VP7

Financial & competing interests disclosure

Miguel O’Ryan was the principal investigator for the Multicenter Human Rotavirus Vaccine Trial sponsored by GlaxoSmithKline Biologicals, and is chairman of the TAG group supervizing a second vaccine effectiveness study of RotaTeq™ currently ongoing in Nicaragua. Miguel O’Ryan has received consulting and lecture fees from GlaxoSmithKline Biologicals. Alexandre Linhares was the principal investigator of studies with the Human Rotavirus Vaccine in Belém, Brazil, and has received research funding from GlaxoSmithKline Biologicals. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.