The US Food and Drug Administration (FDA) just announced that initial results from a Mexican study with GlaxoSmithKline PLC’s <"http://www.yourlawyer.com/practice_areas/defective_drugs">Rotarix vaccine suggest an increased risk of intussusception, reported the Wall Street Journal.
Intussusception is a serious and potentially life-threatening condition that occurs when the intestine gets blocked or twisted. Intestinal obstruction occurs when one portion telescopes into a nearby portion. The most common site is where the small intestine joins the large intestine. Because the two walls of the intestines press against each other, this causes inflammation, swelling, and eventually decreased blood flow. If not detected early, internal bleeding, a hole in the intestines, and infection in the abdomen may occur due to the intestinal tissue dying from the decreased blood flow.
Rotavirus disease is the leading cause of severe diarrhea and dehydration in young infants worldwide. In the US, the disease occurs more often during the winter. Prior to rotavirus vaccines becoming available, most children in the US were infected with rotavirus before the age of two resulting in 55,000-70,000 hospitalizations and 20-60 infant deaths in the US annually. Today, rotavirus disease is estimated to be responsible for the deaths of more than 500,000 infants around the world yearly, primarily in poorer countries.
Rotarix was approved for use in the US in 2008. Babies receive the vaccination at two and four months of age to protect the babies from rotavirus disease, said the Journal, noting that Merck & Co. manufactures a similar vaccine called RotaTeq. Both RotaTeq and Rotarix protect infants against rotavirus. According to the Centers for Disease Control and Prevention (CDC), as of June, 2009, about 72 percent of US infants five months of age had received at least one dose of rotavirus vaccine.
In a statement issued on its Website yesterday, the FDA said the emerging study revealed an increased risk of intussusception during the 31 days following the first Rotarix dose, with most in the first seven days, said the Journal. For the US, these findings translate to potentially 0-4 additional cases of intussusception hospitalizations per 100,000 infants within 31 days of receiving the first dose of Rotarix and also takes into consideration the background rate of intussusception hospitalizations in the US, which is about 34 in 100,000 infants annually, said the FDA.
The FDA noted that preliminary study results are now included to the productâ€™s label, according to the Journal. The study looked at intussusception risks with Rotarix within 31 days after the first vaccination in infants under one year of age, said the Journal. The FDA is now reviewing the findings and will review final data, which is expected next year, explained the Journal. Glaxo is also conducting a post-marketing study in the US into potential safety issues and possible intussusception risks, noted the Journal.
Meanwhile, in March, the FDA told doctors to stop using Glaxoâ€™s Rotarix after it was found to contain a pig virus called porcine circovirus 1 (PCV1). An independent US academic research team discovered the virus using a novel technique that revealed DNA from PCV1 in Rotarix. Follow-up tests by Glaxo and FDA scientists confirmed the findings and that viral components have been present since the early stages of the vaccineâ€™s development, including during clinical studies.