Friday, May 18, 2007

Does Your Newborn Need Rotavirus Vaccine?

I shall be chairing a round-table discussion on rotavirus vaccines tomorrow so I have been doing some reading and thinking.

Of the nearly 11 million deaths that occur annually among children under five years of age, diarrheal disease is the second leading cause. The most common cause of severe gastroenteritis worldwide, rotavirus accounts for 29 to 45 percent of nearly 2 million deaths attributed to diarrheal disease. An estimated 600,000 children die from rotavirus each year, and more than 2 million are hospitalized due to the severe dehydration caused by rotavirus infection.
The disease burden of rotavirus falls starkly and disproportionately on children in developing countries, where adequate and timely medical care is often out of reach: more than 80 percent of rotavirus deaths occur in south Asia and sub-Saharan Africa.

For more information on rotavirus infection read My child has rotavirus infection.

Two live, oral, attenuated vaccines against rotavirus infection (Rotarix®, manufactured by GlaxoSmithKline; and RotaTeq®, manufactured by Merck & Co., Inc.) were licensed by the European Medicines Agency and the US Food and Drug Administration, respectively, in 2006. Clinical trials in Europe, Latin America, and the US have demonstrated that these vaccines are safe and highly efficacious at preventing rotavirus-associated severe gastroenteritis. A number of countries, including some developing countries, have licensed these vaccines, and they are beginning to be introduced in routine immunization programs in some settings.

On February 22, 2007, the US Centers for Disease Control and Prevention (CDC) convened the Advisory Committee on Immunization Practices (ACIP) to review post-marketing safety surveillance data on RotaTeq®, the rotavirus vaccine by Merck and Co., Inc. Because of a suspected association between intussusception (a blockage of the intestine) and an earlier rotavirus vaccine (RotaShield®) that was withdrawn from the US market in 1999, the CDC is monitoring this new vaccine with particular care.

Since the vaccine’s introduction in February 2006 through February 14, 2007, the rate of reports of intussusception following RotaTeq® vaccination recorded through the CDC’s Vaccine Adverse Event Reporting System did not exceed expected background rates in the absence of vaccination. Also, active surveillance being conducted in a population of insured children has not identified any reports of intussusception within 30 days of more than 28,000 administered doses of RotaTeq®. Upon review of this information, the committee expressed no safety concerns regarding use of RotaTeq® and stood by its initial recommendation for routine administration to all US infants at ages 2, 4, and 6 months.

To date, both vaccines have been primarily studied in middle- and high-income countries. But historically, oral vaccines have been shown to perform differently in different regions of the world. The global health community recognizes the need to carry out additional studies of the safety and efficacy of these vaccines in developing countries of Africa and Asia, where the burden of disease is very high.

April 2, 2007 marks the first infant enrolled for RotaTeq® efficacy and safety trial in Asia. Investigators at the International Center for Diarrheal Disease Research in Bangladesh (ICDDR,B) marked a milestone last week with enrollment of the first child in a clinical trial to determine the safety and efficacy of RotaTeq® for use in the region. The trial, supported by PATH and Merck & Co., Inc., is an important step toward rotavirus vaccine introduction in the developing world, where the burden of disease is greatest.

PATH’s Rotavirus Vaccine Program is working in partnership with Merck and GlaxoSmithKline, respectively, to evaluate the use of their rotavirus vaccines in impoverished populations in developing countries. In addition to the trial in Bangladesh, enrollment will begin later this year for studies of RotaTeq® in Mali, Ghana, Kenya, and Vietnam. Studies of GSK’s Rotarix® vaccine are ongoing in South Africa and Malawi. Results from these trials will be critical in enabling global and national policymakers to make evidence-based decisions about the introduction of rotavirus vaccines.

Justin Gillis writes in Washington Post
Wednesday, February 22, 2006; Page A08

Every healthy newborn in the United States should receive a new vaccine designed to protect against an intestinal germ called rotavirus, a federal advisory panel decided yesterday as it set aside theoretical concerns about the vaccine's safety.

The decision means that pediatricians are likely to recommend three doses of the oral vaccine for nearly every child at age 2 months, 4 months and 6 months, beginning almost immediately. The vaccine won approval from the Food and Drug Administration on Feb. 3, and some doctors have received supplies of it.

A few questions I shall be raising

(1) No doubt it will be good for all Malaysian children to receive the 3 doses of the Rotavirus vaccine. The first dose must be given at 2 month. After 6 months, it is no longer effective. However it will only be the rich who can afford it. The Ministry of Health have not included it into their immunisation schedule. Even the rich will feel the pinch as there is also a 4-dose regime of pneumococcal vaccine to be given at the same time. Each dose of pneumococcal and rotavirus vaccine is about RM 300.00 per dose. Hence we are talking about an addition RM 2,100 for vaccination for a newborn baby!

(2) So far the vaccine has been “safe.” However we are dealing with the intestinal bacteria and immunity of a 2 month old baby. We are introducing “live” attenuated (weakened) viruses. Can anyone predict any long term long term effect?

(3) Most of the children will be exposed and be immune to rotavirus by 3 years old. Only a small percentage of these children will suffer severe diarrhea. The majority will suffer mild to moderate diarrhea. Are parents willing to take the risk?

(4)The children who are most at risk are in developing countries and the urban/rural poor in developed countries. We do not have any evidence so far that the vaccine as effective in a developing country as it is in developed countries. Are we targeting the wrong population?

Any other questions you want to raise?

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Anonymous SS said...

Dear Alex,
Landed in your blog after google on Rotavirus contamination.
Beside the points that you have raised, I think the drug company owe us the proof of safety and efficacy of these vaccines. If they’re going to allow contamination in these vaccines, they have to let the people know how much of it is in the vaccines.

10:39 AM  

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