Conjugate vaccines reduced meningitis sepsis rates in England

The incidence of vaccine-preventable bacterial diseases have significantly decreased among children in England during the past 50 years, according to study findings presented at the 2014 European Society for Pediatric Infectious Diseases Annual Meeting.

Natalie G. Martin, MBChB, of the NIHR Oxford Biomedical Research Centre, and colleagues analyzed data from English hospitals from 1968 to 1986 and 1989 onward, as well as data for Oxfordshire and surrounding areas from 1963 to 2011. They specifically looked at hospital admission rates for children younger than 15 years with Haemophilus influenzae, meningococcal and pneumococcal meningitis and sepsis.

The annual age-standardized rate for H. influenzae meningitis varied from 2.86 to 6.72 episodes per 100,000 children between 1968 and 1991, peaking at 6.72 (95% CI, 6.18-7.26) in 1992. Rates decreased by 94% after the introduction of routine H. influenzae type b vaccination in 1992. There was an increase in admissions in the early 2000s, peaking at 1.24 admissions per 100,000 children in 2003. This rate decreased to 0.28 per 100,000 children by 2008. Admission rates for sepsis remained low from 1995 to 2011.

Before 1985, the episode-based admission rate for meningococcal disease remained at a stable five admissions per 100,000 children. There was a small increase during the mid-1970s. Admission rates for Neisseria meningitidis increased in the 1990s, peaking at 34.54 admissions per 100,000 children in 1999. Admission rates decreased to 12.4 per 100,000 children after the meningococcal serogroup C vaccine was introduced in 2011. Person-based admission rates for N. meningitidis decreased by 66% between 1999 and 2011.

Admission rates for pneumococcal meningitis ranged from 1.13 to 2.29 per 100,000 children in England before 1985 and gradually increased through the 1990s and 2000s, peaking at 4.45 admission episodes per 100,000 children in 2006. Rates decreased in 2006 when the 7-valent pneumococcal conjugate vaccine was introduced, dropping to 2.03 episodes per 100,000 children in 2011. Researchers noted a small increase in admission rates for pneumococcal meningitis in 2009 and sepsis in 2010, which decreased after the replacement of PCV7 with 13-valent pneumococcal conjugate vaccine in the infant immunization schedule.

Hospital admission rates for adults aged 65 years and older did not consistently change between 1999 and 2011. Incidence rates for H. influenza, meningococcal and pneumococcal meningitis, and sepsis were higher among males than females. Infants experienced the greatest burden of these diseases.

Andrew Riordan, PhD, of the Alder Hey Children’s NHS Foundation Trust, Liverpool, United Kingdom, wrote in an accompanying editorial that more work can be done to lower the incidence of pneumococcal diseases among children.

“Pneumococcal meningitis has the highest morbidity and mortality in children. Despite widespread use of the PCV7 in the US, pneumococcal meningitis is still the most common bacterial meningitis in American children, mostly due to non-vaccine serotypes. A 13-valent PCV was introduced in the UK in 2011, but there are 80 other serotypes of pneumococcus not included in this vaccine. Further efforts to provide broader protection against pneumococcus are needed,” Riordan wrote.

Although their findings indicate reductions in the incidence of vaccine-preventable pediatric invasive bacterial disease have occurred in England, the researchers concluded: “… There were still many children younger than 15 years admitted to hospital with meningococcal infection, pneumococcal septicemia, or meningitis … showing the importance of ongoing vaccine development and deployment to ensure child health.”

For more information:

Martin NG. Abstract #OS03. Presented at: ESPID 2014; May 6-10, 2014; Dublin.

Martin NG. Lancet Infect Dis. 2014;14:397-405.

Disclosure: See the study for a list of researchers’ financial disclosures.