The UK is experiencing the largest surge of pertussis since the early 1990s, with 138 cases and five deaths reported up to the end of May in infants under 3 months.
There were 1,781 confirmed cases of pertussis in England and Wales in the first five months of 2012, compared to a total of 1,118 cases across the whole of 2011.
This week, Dr Gilberto Chavez and colleagues from California’s department of public health reported the conclusions of their analysis of the 2010 California pertussis epidemic, in which 10 infants died.
Dr Chavez and his team concluded that new vaccination schedules and strategies need to be investigated, as well as more efficacious vaccines.
‘Improvements in pertussis immunisation levels may help to reduce endemic transmission of pertussis and reduce the numbers of infected infants,’ the researchers concluded.
‘However, without a vaccine that is more efficacious and confers lifelong immunity, pertussis will continue to be a threat to the lives of young infants.’
They added: ‘Unfortunately, unlike measles, neither pertussis immunisation nor disease confers lifelong immunity and it will be extremely difficult, if not impossible, to achieve and sustain levels of population immunity high enough to control pertussis using currently available vaccines.’
Until improved vaccines are available, strategies for directly protecting young infants, such as maternal vaccination, must be evaluated for effectiveness, Dr Chavez and his colleagues said.
The Health Protection Agency has said that it believes that waning immunity is likely to be contributing to the ongoing surge in pertussis cases in the UK.
HPA research has previously suggested that pertussis jabs should be given to adolescents, pregnant women and some adults to boost immunity and protect babies too young for vaccines.
In response to the current UK outbreak, the RCGP has said that government advisers should look again whether all at-risk groups should be given extra doses of pertussis vaccine.