Pneumococcal vaccine protection may be over-estimated
By Lilian Anekwe
The Department of Health may have over-estimated the duration of protection offered by the pneumococcal vaccine, official documents reveal.
The pneumococcal polysaccharide vaccine (PPV) – administered to those aged over 65 – may not be as effective as hoped, as the modelling data used to estimate the benefits of the programme may have misjudged the length of time the vaccine is effective.
Health Protection Agency data shows the duration of protection is closer to one year than the previously estimated five, the minutes of the JCVI Pneumococcal subgroup meeting in January reveal.
‘One important finding from the enhanced pneumococcal surveillance carried out by the HPA is that the duration of protection from the vaccine is shorter than previously estimated. Vaccine effectiveness falls significantly after one year following vaccination. Previous studies had estimated protection for around 5 years', it says.
Professor Adam Finn, professor of paediatrics at the University of Bristol and an expert in the pneumococcal infection, said: ‘The vaccine has been used for some time and though the coverage has gone up there has been no fall in non-bacteraemic pneumonia. It must be a disappointment because though no-one knew it would prevent pneumonia, they had hoped that it would.'
Professor Finn said research from the US suggested that older people are likely to benefit from the herd immunity offered by the childhood pneumococcal conjugate vaccine programme.
‘The Department of Health seems to be getting less enthusiastic about it all the time. But having decided to do it has to stick with it, even though the argument for using the polysaccharide vaccine in adults is getting weaker all the time.'