Immunisation Meningococcal B (MeNZBTM)
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Why did the Meningococcal B Immunisation Programme start? Does the MeNZB™ vaccine work? How long does protection last? If antibodies decrease, does that mean children are not protected anymore? Is MeNZB™ safe? Mild/moderate symptoms after MeNZB™ vaccine Severe risks associated with meningococcal disease Severe risks associated with the MeNZB™ vaccine Why did the programme end? What happens now? Did the Meningococcal B Immunisation Programme achieve what it set out to do? What have we learned? Why did the Meningococcal B Immunisation Programme start? Since 1991, there have been persistently high rates of meningococcal B disease in New Zealand. In 1997 there were 235 meningococcal B epidemic strain cases, rising to 370 at the peak of the epidemic in 2001. A mass immunisation programme started in July 2004 to protect New Zealanders under the age of 20 from the specific strain causing most cases of meningococcal disease in New Zealand. By 2007, number of epidemic strain cases had fallen to 47. The Meningococcal B Immunisation Programme ended in June 2006, although the vaccine continued to be routinely offered to preschoolers until June 2008. In that time, more than 1.1 million young New Zealanders received the MeNZB™ vaccine. About 80% of all under-20-year-olds have received three or more doses of MeNZB™. For Māori, the figure is about 72%. The vaccine is still available for people considered to be at heightened risk of meningococcal disease. Back to top Does the MeNZB™ vaccine work? The latest findings from an ongoing Victoria University study estimate that children who have received at least three doses of MeNZB™ are still three times less likely to contract the epidemic strain of meningococcal disease than those who were not immunised. Unpublished results to 31 December 2007 estimate vaccine effectiveness at 69% (95% confidence interval: 54-79%). In other words, it is estimated that the vaccine will protect 69 out of 100 children who have had three doses. The MeNZB™ vaccine has protected many young New Zealanders and helped curb the epidemic. However some vaccinated people have still contracted the disease. This modelling also suggests that the vaccine effectiveness continues for at least 12 months after the third dose. Earlier findings from this work have been published in the American Journal of Epidemiology. An abstract can be found at http://aje.oxfordjournals.org/cgi/content/abstract/166/7/817 Although there are now fewer epidemic strain cases, meningococcal disease has not entirely disappeared. There are several strains causing meningococcal disease in New Zealand and MeNZB™ vaccine protects against only one of them. Like all vaccines, MeNZB™ is not 100 per cent effective. If you are concerned that you or someone in your household has meningococcal disease, call a doctor or medical centre right away. Back to top How long does protection last? If antibodies decrease, does that mean children are not protected anymore? We still do not know exactly how long protection lasts but a decrease in antibodies may not necessarily mean that children are not protected. We think that there may be other immune factors that protect against meningococcal B disease that we cannot measure. Based on the Victoria University modelling, there is evidence that the MeNZB™ vaccine is still providing protection to young New Zealanders. The MeNZB™ vaccine was not expected to provide life-long protection. Back to top Is MeNZB™ safe? Intensive safety monitoring throughout the Meningococcal B Immunisation Programme was overseen by an independent group of national and international experts. They concluded that the monitoring gave them confidence regarding the safety of the MeNZB™ vaccine. MeNZB™ underwent clinical trials before being used in New Zealand. This did not extend to phase three trials. The decision not to carry out phase three trials was made in order to protect children and young people as quickly as possible. This approach was endorsed by the World Health Organization (WHO) and leading public health experts who judged that there was already sufficient information that showed that vaccines similar to MeNZB™ were effective and safe when given to large numbers of people. Serious adverse events following immunisation are rare but can occur with any vaccine, including MeNZB™. Some, like anaphylaxis (a severe allergic reaction), can be linked to vaccination. Other serious adverse events happen by chance after immunisation. In these cases, scientists have looked to see whether there is a link to the vaccine that was given and have found none. Just because an adverse event follows immunisation, it does not automatically mean it was caused by a vaccine. All medicines and vaccines have risks and benefits. Most vaccine reactions are mild and temporary, and are related to immune response. The risk of serious complications in connection with immunisation is very low, compared to the risk of complications if a child actually falls ill with the disease. Back to top Mild/moderate symptoms after MeNZB™ vaccine In most infants symptoms last only for two to three days and may include: Fever equal to or over 38oC Redness, swelling and tenderness at the injection site Diarrhoea and vomiting Unsettledness Back to top Severe risks associated with meningococcal disease One in 20 children who contract this disease will die One in five to one in 20 children will develop brain damage, deafness, be left with damaged skin or require limb amputations after meningococcal disease One in four children will be left with long term behavioural or learning difficulties Back to top Severe risks associated with the MeNZB™ vaccine To date no severe risks have been identified after MeNZB™ vaccine. Back to top Why did the programme end? The Meningococcal B Immunisation Programme for under-20-year-olds ended in 2006. Routine MeNZB™ immunisation for babies and preschoolers ended from June 2008. Meningococcal B epidemic strain disease has decreased, so the vaccine is no longer needed to control an epidemic. The vaccine is still available free to people with a high medical risk such as those who suffer from: Actual or functional asplenia Sickle cell anaemia Deficiencies of the terminal complement components Individuals with HIV infection, who may be safely immunised with meningococcal polysaccharide vaccines. The MeNZB™ vaccine is no longer routinely given however it is still available free if a parent of a child or young person under 20 years of age requests the vaccine, and the doctor thinks the child is at greater risk of contracting the disease. More information on the ending of Meningococcal B immunisation programme is provided: on the Beehive website - Successful MeNZB™ campaign comes to an end (www.beehive.govt.nz) on the Immunisation Advisory Centre website - Meningococcal MeNZB™ epidemic vaccine programme ends (www.immune.org.nz) in this letter from the combined ITWG/MeNZB Expert Advisory Committee - Expert recommendations on ending routine MeNZB immunisation for babies and preschoolers (PDF, 27 KB). Options for the future of meningococcal B vaccine (MeNZB™) in the childhood immunisation schedule Back to top What happens now? It is difficult to predict how a meningococcal B epidemic will unfold. Though these epidemics typically last 20 years or more, the number of cases can rise and fall repeatedly over that time. The latest unpublished findings from an ongoing study estimate that the programme has helped prevent 136 cases and four deaths to 31 December 2007. These numbers are lower than earlier estimates because the estimates were based on a longer time period and the number of cases had already started to reduce by the time the immunisation programme began in 2004. The Ministry of Health will continue to monitor meningococcal disease epidemic strain rates. There is a limited supply of MeNZB™ vaccine available should it be needed. Scientists are developing a broader spectrum vaccine that may protect against all meningococcal B strains, including New Zealand’s epidemic strain. Back to top Did the Meningococcal B Immunisation Programme achieve what it set out to do? The Meningococcal B Immunisation Programme helped control an epidemic of a specific strain of meningococcal B disease. The epidemic waned faster than would have been expected if there had been no intervention, however it is important to remember that even though there are now fewer cases, the disease has not entirely disappeared. The programme was not just about vaccination – it was also about raising awareness of meningococcal disease and its signs so that New Zealanders knew to seek medical help urgently if they suspected they or someone in their household had the disease. With the support of health professionals and communities throughout New Zealand, the programme achieved the highest ever numbers of vaccinations in a mass campaign in New Zealand with immunisation coverage rates of 90% in South Auckland and Pacific communities where children were at highest risk of this disease. Nationwide about 80% of all under-20-year-olds received three doses of MeNZB™ vaccine. For Māori, the figure is about 72%. Back to top What have we learned? We take very seriously the need to ensure that people have access to accurate information about the MeNZB™ vaccine. Throughout the programme this was provided in detail to health professionals and on the Ministry’s website, as well as through advertisements, brochures and consent forms. Health professionals were provided with information and resources to enable them to discuss and answer questions about MeNZB™ immunisation with parents and guardians before they gave consent to their child receiving MeNZB™. Although there was a great deal of information about the MeNZB™ vaccine available throughout the immunisation programme, it is clear that some people were expecting this vaccine to provide much longer protection than some media reports about antibody levels have suggested. The Ministry stands by the information about the length of protection that was included in numerous meningococcal B documents and consent forms made available to health practitioners from 2004. Our view remains that the vaccine protects for a few years, though we do not know the exact duration. The number of cases of the disease since the vaccine was introduced supports this view. The research about the MeNZB™ vaccine that was publicised in the media in July 2008 showed that antibody levels can drop quickly, but this does not necessarily mean that immunity drops because the relationship between antibodies and immunity is not clear. There is no absolute way of measuring immunity to meningococcal disease. Some vaccines offer longer-lasting protection than others, for example hepatitis B vaccine is thought to provide life-long protection, while diphtheria and tetanus vaccine protection is expected to last at least 10 years and whooping cough (pertussis) vaccine protection may last anywhere from 3 to 12 years. We expected protection from MeNZB vaccine to last several years and this is still the case. However we cannot say exactly how long protection lasts. Back to top Back to the Diseases and Vaccines page Website feedback We welcome your feedback on this page. Page last updated: 26 May 2009