Vaccines for meningococcus B and rotavirus expected
within five years
Within the next five years, meningococcal B and rotavirus
vaccines can be expected. And within the next 10 years, there could be
an HIV vaccine, a malaria vaccine, specific vaccines for the elderly (against
Herpes zoster, Streptococcus pneumoniae, and, perhaps, respiratory
syncytial virus), and a vaccine against Herpes simplex. There is also
likely to be at least one therapeutic vaccine, probably for chronic hepatitis
B or for genital warts.
These predictions were made by Dr Norman Begg, director
of medical affairs, HIV, vaccines and anti-infectives, GlaxoSmithKline,
at a recent meeting on vaccination organised by the Royal Institute of
Public Health and Hygiene.
Dr Begg said that therapeutic vaccines (which he
called pharmaccines) represented a new philosophy. They were technically
similar to conventional vaccines — being composed of antigen, adjuvant
and possibly a carrier — but were designed to stimulate the immune system
to eliminate chronic infectious pathogens or to destroy cancer cells by
modulating specific immune responses. Applications in chronic infectious
disease included hepatitis B and tuberculosis.
In cancer trials, clinical response to date was
limited, with survival benefit measured in weeks rather than months or
years, but it was early days yet, he said. Therapeutic vaccines also had
possible uses in allergy treatment, with asthma and food allergy being
among current areas of research.
Developments in vaccine delivery were also likely,
said Dr Begg. Intranasal, intradermal and transcutaneous administration
are all under investigation. The intradermal route, in particular, had
great potential.
“If you had to choose a site to deliver a vaccine
to, it would be the dermis. The area is packed with macrophages and there
is no doubt this would significantly enhance immune response to many antigens,”
he explained.
There was perhaps less chance of progress with vaccine
combinations. At least six antigens could now be given together and, although
it would be ideal to be able to give all childhood vaccines in one syringe,
it might be that this approach had reached its limit. Interference between
antigens was a possibility — this might not be clinically important but
it could be an issue with the licensing authorities. Stability could also
be a problem. Another issue was parental acceptability. There was already
a fairly negative attitude to combination vaccines in the United Kingdom.
“I do not for a moment endorse that, but it may
be difficult to sell to the public if we put too much in one syringe,”
said Dr Begg.
— Contributed.
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