MADRID – Cases of invasive meningococcal disease in English 1 year olds dropped fourfold in the first year after the multicomponent group B meningococcal (MenB) vaccine (4CMenB, Bexsero) was added to the national infant immunization list, Shamez Ladhani, MD, Ph.D, reported at the annual meeting of the European Society for Paediatric Infectious Diseases.
“In 1 year olds, we have seen a significant decrease in the number of cases, compared with the number of cases predicted. I suspect the vaccine effectiveness is close to 94% against meningococcal group B,” said Dr. Ladhani of Public Health England, London.
Dr. Shamez Ladhani
Meningococcal meningitis and septicemia remain the leading cause of death for children under 5 in the UK. Public awareness of this threat is high, so 4CMenB has been well accepted. Of eligible infants, 96% have received the first dose and 89% the second. The first cohort became available for the 12-month booster dose in May 2016.
Between May and December of 2016, the Public Health England intensive surveillance program confirmed six cases of invasive meningococcal disease. During the same time frame in 2015, there were 24 cases, whereas, during the 4 years prior to introduction of 4CMenB, the average was 18 cases per year.
Three of the six 1-year-olds had meningitis, and three had septicemia. One was admitted to an ICU. None died. None had comorbid conditions placing them at increased risk. Five of the six children with invasive meningococcal disease had received two doses of the vaccine, and one child became ill 3 months after receiving the third dose.
The vaccine is licensed to be given as a four-dose series: three primary doses plus one booster dose. UK health officials deemed that excessive and not cost effective. Based on data from the vaccine trials, they determined that three doses are sufficient. This cut the cost of the national program by 25% while maintaining protection (Lancet. 2016 Dec 3;388(10061):2775-82).
Pediatricians from other countries were extremely curious about this innovative immunization program. What about vaccine side effects in infants? they asked.
Dr. Ladhani replied that studies in Australia, Northern Ireland, and Scotland have all shown a small uptick in mild fever and irritability in the first 3 days after the first dose of 4CMenB. It’s less of an issue with the second dose.
“One dose is not protective. You need two. Parents understand that, while these side effects are annoying, the risks associated with meningitis are far greater. They are very, very accepting of the vaccine,” according to Dr. Ladhani.
What about using 4CMenB in teenagers? physicians asked.
Dr. Ladhani predicted that the infant immunization program will have zero effect in adolescents. Teens are the main carriers of meningococcal bacteria. So, in theory, vaccinating them could not only protect the adolescents themselves but could benefit the whole population through herd immunity.
“The problem is we don’t have solid evidence that Bexsero protects against carriage. A massive carriage study is underway in Australia. It should provide data in 2 or 3 years. If we do see a carriage effect, then vaccinating teenagers becomes a very attractive option because you protect them and others around them,” he explained.
Dr. Ladhani reported having no financial conflicts regarding his study, funded by Public Health England.