Rotavirus vaccine and intussusception
Editor: Response to The Future of research into rotavirus vaccine (BMJ 2000: 321).
As you point out in the editorial, it is the truth that some people assume that inaction is a morally neutral state. This is dramatically true for the developing world, such as Latin American countries, because our politicians and public health authorities have not become aware that both action or inaction have consequences with costs that are important to establish. Moreover, nobody wishes to be responsible for the cost of the decisions taken. Then, it is necessary to know the risks and benefits before taking a decision like withholding the tetravalent rhesus rotavirus vaccine.
On the other hand, there are few aspects in favor of initiating a randomized controlled trial with this vaccine:
First, it is necessary to know the efficacy/effectiveness of this vaccine in a country with high mortality rates.
Second, the information regarding epidemiology of intussusception (IS) in developing countries is scarce. Probably, rates are lower than in developed countries. Therefore, the risk of IS associated to this vaccine is not necessarily that observed in the United States.
Third, large effectiveness studies will give additional information about the potential risk of IS with the use of rotavirus vaccine.
Finally, assuming the worse scenario of a 25% fatality rate from IS, 2000 to 3000 of the deaths caused by the rotavirus vaccine will also occur without the vaccine.
Data from Venezuela, a country with low mortality rate for rotavirus diarrhea (1 in 6000 infants <1 year of age die each year due to rotavirus - unpublished data) indicate that in a cohort of 600,000 birth/year, there will be approximately 100 deaths caused by rotavirus in this population. Supposing that the risk of IS associated to the vaccine is 1/10,000, there will be 60 cases and 15 deaths (25% fatality rate) from IS. This means that withholding the vaccine, we will prevent 15 deaths due to IS but 80 (vaccine will prevent 80% of death) infants will die from rotavirus diarrhea. This is the kind of mathematics we should apply in order to take our own decisions in developing countries.
Chief of Enteric Disease Section, Instituto de Biomedicina, MSDS/UCV.
Competing interests: No competing interests