The Netherlands is currently experiencing a sharp increase in cases of serogroup W meningococcal disease . According to the Dutch National Institute for Health and the Environment (RIVM), in the first four months of 2018, 57 people have been hospitalized due to a meningococcal W infection. Additionally, 11 people have died in this timeframe, matching the previously reported number of deaths for the entirety of 2017.
There are six serogroups of Neisseria meningitidis bacteria (A, B, C, W, X, & Y) that cause most meningococcal diseases worldwide . Prior to 2015, serogroup W meningococcal disease was rare in the Netherlands, with approximately four cases per year between 2010 and 2014 . In 2017 however, 80 cases of the disease were reported, comprising 40% of the annual cases of meningococcal disease in the country.
Approximately 10% of people carry Neisseria meningitidis in the back of their throat and nose asymptomatically . Disease is caused when the bacteria spreads to other parts of the body, such as the bloodstream or brain meninges . It can be transmitted to others through exchange of respiratory droplets or saliva by close contact, such as coughing, sneezing, or kissing . The two most common meningococcal diseases are meningitis and septicemia . Symptoms of meningitis include fever, headache, stiff neck, vomiting, and sensitivity to light. Symptoms of septicemia, or blood poisoning, include fever, fatigue, vomiting, chills, body aches, and a dark purple rash, caused by bleeding under the skin [1,5].
In the current rise of meningococcal W cases in the Netherlands, patients are more frequently presenting with septicemia than meningitis, which is more common in serogroup B infections [1,3]. However, doctors are also seeing more atypical clinical manifestations, such as pneumonia and arthritis, as well as gastrointestinal symptoms [1,3]. The head of the Netherlands Reference Laboratory for Bacterial Meningitis (RBM), Arie van der Ende, also states that people are continuing to develop disease outside of the winter months, which is unusual .
Since 2002, children in the Netherlands have received a vaccine against meningococcal serotype C at 14 months old . However, with the increase in meningococcal W, the Dutch Ministry of Health, Welfare and Sport announced in September 2017 that children will be offered the MenACWY vaccine instead (which protects against strains A, C, W, and Y), beginning in May 2018. The vaccine will also be offered to 14-year-olds, as teenagers have an increased risk of spreading meningococcal bacteria . However, due to a vaccine shortage, they will not be eligible until October 2018 . Those who were born between May 1 and December 31, 2004 will be eligible this Fall, and starting in 2019, the vaccine will be offered to teenagers at any point in the year they turn 14 . The RIVM is hopeful that this vaccination campaign will protect not only those have received the MenACWY vaccine, but also reduce the spread of the bacteria to protect the whole population at-risk.