Porcine circoviruses and rotavirus vaccines
GACVS reviewed new data on the fi nding of porcine circovirus DNA in Rotarix (GlaxoSmithKline) and RotaTeq (Merck & Co.), two oral vaccines for preventing rotavirus gastroenteritis. In March 2010, GlaxoSmithKline confirmed a report from academic investigators that Rotarix contained DNA from porcine circovirus type 1 (PCV1). GACVS met by teleconference on 25 March 2010 to discuss this finding, and issued interim advice regarding the safety of the vaccine. In May 2010, Merck reported that DNA from porcine circovirus type 2 (PCV2) had been found in RotaTeq.
Neither PCV1 nor PCV2 is known to infect or cause disease in humans. GlaxoSmithKline reported that PCV1 DNA has been identified in both the master cell bank and master viral seed used for vaccine production, and thus has been present in the vaccine throughout its clinical development, including in the vaccine used in prelicensure clinical trials. Initial data reported by GlaxoSmithKline suggest that Rotarix contains infectious PCV1, however PCV1 does not result in productive infection in human cell lines. Analysis of prevaccination and postvaccination serum samples from 40 infants who participated in clinical trials of Rotarix revealed no evidence of serological response to PCV1. DNA from PCV1 was detected in initial postvaccination stool samples (on days 3 or 7) in 4/40 infants; results were inconclusive on a stool sample from 1 additional infant. None of the infants had positive stool samples later.
Merck reported fi nding low levels of PCV1 and PCV2 DNA in bulk lots and fi nal-container lots of RotaTeq. The amount of PCV DNA found in RotaTeq is consistent with introduction from irradiated trypsin, and infectivity assays are under way.
Additional information on both products is expected from both manufacturers and from other investigators.
The safety of Rotarix and RotaTeq is supported by large prelicensure clinical trials and extensive postlicensure safety experience. Worldwide, over 69 million doses of Rotarix and 37 million doses of RotaTeq have been distributed. Rotavirus gastroenteritis is the most common cause of severe diarrhoeal disease in young children throughout the world, causing an estimated 527 000 deaths annually among children aged <5 years. Given the extensive clinical data supporting the safety of both Rotarix and RotaTeq, and the benefits of rotavirus vaccination, GACVS considers that the benefits of vaccination far outweigh any currently known risk associated with the use of either vaccine. GACVS will continue to review data as they become available and will update this statement as necessary.