INVASIVE meningococcal disease (IMD) is a rare but life-threatening bacterial infection that can progress rapidly, causing severe complications or death within hours.
Often mistaken for the flu in its early stages, it poses a high risk in crowded settings such as dormitories, military camps, and pilgrimage sites.
Medical advisor Dr Hazlee Abdul Hadi emphasises that despite its low incidence, vaccination is crucial in preventing outbreaks and saving lives.
In Saudi Arabia, IMD vaccination has been made compulsory in order to enter the country, especially for pilgrims going to do Umrah or Hajj.
Dr Hazlee explained that crowded environments increase the risk of spreading IMD, as the disease is highly contagious and can be transmitted through respiratory droplets, even with minimal interaction.
"When people are vaccinated, say 85 per cent people are vaccinated for the pilgrimage [involving] millions of people around the world, the antibodies created by the vaccine will not allow the disease to spread to others easily, causing deaths," he said.
He added that most deaths in these settings are caused by respiratory and cardiovascular diseases, including influenza, followed by IMD as another significant contributor.
Dr Hazlee added that despite early intervention, IMD has a 10 to 15 per cent fatality rate. Meanwhile, among survivors, 10 to 20 per cent may suffer from long-term complications such as hearing loss, organ damage or neurological issues.
He also emphasised that early intervention for IMD is often rare since during the first four to 12 hours, IMD patients typically experience non-specific flu-like symptoms such as fever, irritability, gastrointestinal symptoms and sore throat, which are often mistaken for the flu, leading to misdiagnosis.
In the 12th to 15th hour, he said that characteristic symptoms would be hemorrhagic rash, neck pain, meningismus or photophobia followed by confusion or delirium, seizures, unconsciousness and possible death within the 15th to 24th hour.
"IMD is contagious and can be transmitted from person to person through droplets of respiratory or throat secretions from an infected individual. Though the prerequisite for IMD is nasopharyngeal carriage of N. meningitidis, it is not known why IMD does not develop in all individuals exposed to N. meningitidis," Dr Hazlee added.
Although undiagnosed IMD happens to many elderly and children, similar to what happened during Covid-19, he said that between five and 20 per cent of the general population are asymptomatic IMD carriers.
He added that IMD leads to death in a matter of hours due to its rapid course of progression, including an average incubation period of IMD of four days.
"IMD progression is usually faster in young patients, especially infants, although they may present with less specific symptoms than other age groups," he said.
Dr Hazlee reminded that although IMD results from an interplay of host, pathogen, and environment-related factors, it could occur in anyone, and individuals of every age are at risk of developing the disease.
Though Malaysia has one of the lowest IMD case rates, he said that it is still important to get vaccinated as a part of preventive measures, where the vaccine types include the MenACWY (quadrivalent conjugate) vaccine.
"You can get this vaccine at any Tabung Haji clinic that not only provides this type of vaccine to pilgrims but also to those travelling to countries that require vaccination," he said.
Dr Hazlee reported that the IMD vaccine's effectiveness in controlling disease outbreaks has been demonstrated throughout history, such as in 2015 when the MenACWY vaccine helped curb the spread of serogroup W meningococcal disease.
Before receiving the vaccine, he emphasised the importance of consulting a doctor to assess any preexisting health conditions that may lead to adverse reactions.
"For those with severe allergic reactions to it, such as experiencing difficulty breathing, they could be exempted from the obligation to take the vaccine, but doctors should properly inform the patients and provide a letter explaining the situation," he added.
"The vaccine takes about seven days to produce antibodies, and travellers or pilgrims should ideally wait 10 days before travelling to allow antibodies to form," he concluded.