A new experimental meningitis vaccine that protects against four strains of the bacterial disease has been successfully tested on babies in the UK and Canada. The news is welcomed by experts and is thought to bring the world a step closer to eradicating the disease.
The study, which was sponsored by Novartis Vaccines and Diagnostics, was carried out by Dr Matthew D. Snape of the Oxford Vaccine Group, University of Oxford, UK, and colleagues and is published in the January 9/16 issue of the Journal of the American Medical Association (JAMA).
Estimates show that 10 to 14 per cent of the 1,400 to 2,800 Americans who contract invasive meningococcal disease every year will die. The US Advisory Committee on Immunization Practices recommends all 11 to 18 year olds receive a tetravalent vaccine (protects against serogroups A, C, W-135, and Y).
However, the currently licensed vaccine does not have a high immunity success rate in babies, where the disease is most prevalent, wrote the authors.
Snape and colleagues carried out a randomized controlled study to find out how much immunity could be conferred by a new tetravalent meningococcal vaccine called by the experimental name MenACWY (made by Novartis Vaccines and Diagnostics). Unlike the currently licensed vaccine, the new experimental one is based a natural version of the diphtheria toxin.
421 healthy babies in the UK and Canada were randomized to receive either one of three different dosing schedules of tetravalent MenACWY, or a monovalent vaccine (against serogroup C only).
The researchers measured the babies’ antibody levels after vaccination, assessed the safety of the vaccine, and any adverse reactions.
They found that:
- MenACWY was well tolerated.
- It gave immunity against serogroups A, C, W-135, and Y when administered in two dosing schedules: at 2, 3 and 4 months of age, and at 2, 4 and 6 months of age.
- At least 92 per cent of babies who had the vaccine at age 2,3 and 4 months had sufficient antibodies against all four strains of meningococcal disease.
- Babies who received the vaccine at age 2,4, and 6 months had similar levels of protection for strains C, W-135, and Y, but protection against serogroup A was lower at 81 per cent.
- In a further group that had the vaccine at 2 and 4 months, with a booster at 12 months, 84 per cent of the babies had sufficient protection against strains C, W-135, and Y, and 60 to 66 per cent were protected against strain A after the first two doses.
- This protection went up to 95 per cent against the first three strains, and 84 per cent against strain A, after the 12 month booster.
The authors concluded that:
“MenACWY was well tolerated and immunogenic in the first year of life.”
“This vaccine therefore extends the immune protection provided by the monovalent MenC vaccine to serogroups A, W-135, and Y in infancy,” they added.
In an accompanying editorial, Dr Lee H. Harrison, of the Infectious Diseases Epidemology Research Unit, University of Pittsburgh, reviewed progress in meningitis prevention and commented on the study by Snape and colleagues.
He wrote that the study represented a “substantial advance” in the vaccine prevention of meningitis because it:
“Provides evidence for a well-tolerated and immunogenic tetravalent (serogroups A, C, W-135, and Y) conjugate vaccine for infants.”
Assuming it eventually gains approval and is licensed, there will still be some questions. For example, how long will the immunity last? And will children need extra doses between receiving the vaccination in infancy and the later series in adolescence?
However, these practical issues notwithstanding, Harrison ends on an optimistic note:
“Taken together with other ongoing progress, the outlook for comprehensive global prevention of this devastating disease has never been better.”
“Immunogenicity of a Tetravalent Meningococcal Glycoconjugate Vaccine in Infants: A Randomized Controlled Trial.”
Matthew D. Snape; Kirsten P. Perrett; Karen J. Ford; Tessa M. John; David Pace; Ly-Mee Yu; Joanne M. Langley; Shelley McNeil; Peter M. Dull; Francesca Ceddia; Alessandra Anemona; Scott A. Halperin; Simon Dobson; Andrew J. Pollard.
JAMA 2008 299: 173-184.
Vol. 299 No. 2, January 9/16, 2008.
“A Multivalent Conjugate Vaccine for Prevention of Meningococcal Disease in Infants.”
Lee H. Harrison.
JAMA 2008 299: 217-219.
Vol. 299 No. 2, January 9/16, 2008.
Sources: JAMA press release, journal articles.
Written by: Catharine Paddock