BOSTON (Reuters) - Merck’s chickenpox vaccine Varivax not only loses its effectiveness after a while, but it has also changed the profile of the disease in the population, U.S. researchers reported on Wednesday.>>> Discuss This Story
BOSTON (Reuters) - Merck’s chickenpox vaccine Varivax not only loses its effectiveness after a while, but it has also changed the profile of the disease in the population, U.S. researchers reported on Wednesday.>>> Discuss This Story