A recent study proved that GlaxoSmithKline's (GSK. L) vaccine Cervarix has an edge over Merck & Co's (MRK. N) rival Gardasil. Cervarix generated a more powerful immune response against a sexually transmitted virus that causes cervical cancer as compared to Gardasil.

Data analysis from the study involving 1,106 women aged 18-45 years revealed that Cervarix provided more than two times higher neutralising antibody levels for human papillomavirus (HPV) type 16 and more than six times higher for HPV 18 than Gardasil.

Study also revealed that Cervarix also induced 2.7 times more memory B cells for both virus strains.

Gary Dubin, head of clinical development for Cervarix, said the results were impressive and suggested Glaxo's vaccine had an edge over its rival thanks to the novel adjuvant, or additive, used in its manufacture.

He added: "The fact that the immunogenicity of the two vaccines is different is an important factor for (clinical) practitioners to consider. It is just one piece of information but it is an important piece."

Gardasil's makers said the comparative data was not clinically relevant because there was no evidence a higher immune response measured seven months after first vaccination made any difference to the long-term risk of developing cancer.