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PRIORITY PRESS - 89th Annual Meeting of the Canadian Paediatric Society

London, Ontario / June 6-9, 2012

London, Ontario - Public distrust in vaccines appears to be increasing, fuelled by factors that include anti-vaccination voices throughout the Internet. A recent survey of Canadian parents showed that while the majority do have their children vaccinated, distrust of new vaccines is apparent, with many questioning the need for so many vaccines and their relative safety. Health care providers therefore need to understand what is driving this vaccine confidence gap and be prepared for discussion. Although schedules differ by province and territory, recommendations from the Canadian Paediatric Society indicate that infants should receive a dose of the meningococcal C conjugate vaccine at 12 months, with booster doses of either a conjugated MenC or MenACWY vaccine, ideally at age 12. As serogroup B now causes the majority of invasive meningococcal disease in Canada, especially in young children, hopes are high for a novel vaccine against this serogroup.

Chief Medical Editor: Dr. Léna Coïc, Montréal, Quebec

There is concern that a vaccine confidence gap is growing in the public at large, especially confidence in new vaccines, and health care providers must recognize the complex reasons fuelling this gap and address the public’s concerns.

Factors Influencing Acceptance of Vaccines

“The vaccine community demands rigorous evidence on vaccine efficacy and safety when introducing any new vaccine,” William Fisher, PhD, Professor of Psychology, University of Western Ontario, London, told delegates here. For the public, acceptance of vaccines is not nearly as simple and is driven not only by scientific and economic evidence but rather a mix of psychological, sociocultural and political factors, all of which need to be understood and taken into account. Indeed, the offering of a vaccine by a health care professional and uptake of that vaccine is actually a complex process, what Dr. Fisher calls a “conversant dance” between physicians and patients which
requires both parties to be well-informed, well-motivated and behaviourally skilled. “Most physicians encounter concerns about vaccines on a daily basis,” Dr. Fisher noted.

Public concern about vaccines is fuelled by a variety of sources. The most powerful and potentially negative accounts originate from the Internet whereby the public may have their fears stoked about the need for vaccination in general. The public may also question motives from industry for recommending widespread vaccine uptake. Over the past decade, an array of new vaccines has been developed,
complicating vaccination schedules and the appointments needed to get children vaccinated.

Vaccine safety is constantly being questioned, even if reported adverse events are almost always coincidental and not causal. “Vaccines have also been victims of their own success,” Dr. Fisher added. Since the widespread eradication of many childhood infectious diseases in developed countries, neither parents nor health care professionals have seen the devastation that these diseases used to cause so the incentive to have their child vaccinated is much diminished.

Parent Survey on Vaccination

Acceptance for vaccines among Canadians also appears to be “broad but shallow.” As Dr. Fisher noted, 89% of parents recently surveyed by Ekos Research in 2011 (submitted to the Public Health Agency of Canada) said that their child had received all vaccines that were recommended for children of their age. If they said no, the influenza, human papillomavirus and chickenpox vaccines were most likely to be the ones they had not received.

When polled for the reasons why their child had not been immunized, 28% of respondents indicated that vaccines are not necessary, 17% had concerns about safety, 16% indicated that they do not believe in vaccines and 12% said vaccines had too many side effects. Another 10% of respondents indicated that they found the decision to have their child vaccinated difficult to make, again largely because of possible side effects (22%) but also because of controversial or conflicting evidence (18%). Some 12% felt there was not enough information about vaccines in order to make that decision less difficult.

The same survey also revealed that approximately half of respondents felt that newer vaccines are not as safe as the older ones and some 43% were more concerned about the safety of vaccines now than they were 5 years ago. Many also felt adverse reactions to vaccines do not get enough media attention and close to one-third felt that children today receive too many vaccines. The good news is that almost all Canadian parents follow their physician’s advice to have their child vaccinated as recommended and tend to believe their
physician more than information they read on the Internet, Dr. Fisher noted.

Using the new multicomponent meningococcal serogroup B (4CMenB) vaccine as an example, Dr. Fisher suggested that health care professionals should prepare parents for acceptance of the new vaccine; although very rare, meningococcal disease is potentially catastrophic. “Clinicians need to tell parents about the complex vaccine schedule and talk about potential side effects that, while manageable, do exist,” he told delegates. “We have to do our part to inform parents and facilitate consideration of adoption of the 4CMenB [vaccine] and other new vaccines.”

Vaccination Against Invasive Meningococcal Disease

One of the important features of Neisseria meningitides is how short the period of incubation is, as swift as 48 hours prior to symptom onset. This is important because an anamnestic (memory) response cannot be relied upon to prevent disease; rather, as pointed out by Dr. Marina Salvadori, University of Western Ontario, “you need to have high levels of circulating antibody at all times because as soon as the bacteria gets into your blood, you have to have antibody there to wipe it out.” Primary vaccination thus cannot be expected to provide
lifetime protection against N. meningitides and boosters will be needed, although how often they will be needed is still debated as the duration of protection is not known.

Recommendations for vaccination against invasive meningococcal disease (IMD) were made by the National Advisory Committee on Immunization (NACI) in 2009 and were updated by the Canadian Pediatric Society (CPS) in 2011 (Paediatr Child Health 2011;16(8):485-6). Because historical experience showed that immunity following conjugate C vaccination in early infancy wanes by even 1 year of age, the CPS now recommends infants receive 1 dose of the conjugate C vaccine at 12 months although the same vaccine may be given at 2, 4 and 12 months in infants at increased risk for IMD (primary antibody deficiency disorders, sickle cell anemia).

If infants did receive the conjugate C vaccine before 12 months of age, they require a second dose the second year of life. The vaccine may be given as an adolescent booster as well, ideally at 12 years of age. Either one of the available quadrivalent meningococcal conjugate vaccines against serogroups A, C, Y and W-135 (MenACWY-CRM [Menveo] and MenACWY-D [Menactra]) may also be given at 2 years of age in groups at increased risk for IMD as well as an adolescent booster. Groups who are at high risk, notably children who do not have a spleen, may also be given MenACWY-CRM at 2 months of age, Dr. Salvadori noted.

Serogroup B Vaccine

“Serogroup B disease is actually now more common than serogroup C disease,” Dr. Salvadori reported. This is likely due to the widespread uptake of the conjugate C vaccine, which protects not only those who are vaccinated but also those around them due to herd immunity. As the CPS 2011 update pointed out, serogroup B disease occurs endemically in Canada, with a peak incidence in children younger than 5 years of age. Over 70% of cases in this age group are now due to serogroup B, according to the 2011 CPS update.

Unlike the other polysaccharide capsules, the B capsule of the organism is poorly immunogenic and making a traditional conjugate vaccine against serogroup B proved impossible. Using an approach called “reverse vaccinology,” researchers sequenced the entire meningococcal B genome and identified 3 antigens important to the survival, fitness and virulence of the organism.

An outer membrane vesicle from a New Zealand outbreak strain was added to these 3 antigens to produce the 4CMenB vaccine. Studies have been carriedout to evaluate the novel vaccine in adults, adolescents and infants and it is estimated to protect against current meningococcal B strains in 75% of infants and 83% of adolescents and adults. Since serogroup B now causes the majority of IMD in Canada, such a vaccine would be a major breakthrough.

Summary

Childhood immunization has been a major public triumph of modern medicine but its purpose is being undermined by concerns that vaccines, especially the new vaccines, are unnecessary and not safe enough. Physicians and allied health care professionals must equip themselves with the information and skills needed to motivate parents to accept vaccination, especially when newly introduced and unknown. Recommendations to vaccinate infants and adolescents against IMD vary from province to province but were updated recently
by the CPS and they should be noted.

This report is based on presentations given during the educational Luncheon Symposium (S1) entitled “Paediatric Meningococcal Immunization: Guidelines and Issues of Vaccine Uptake,” Wednesday, June 6, 11:45-13:15, during the 89th Canadian Paediatric Society Annual Conference, June 6-9, 2012, in London, Ontario. Unless specifically stated otherwise, the opinions presented in this report are those of individual(s) presenting; they do not represent the opinions of the Canadian Paediatric Society nor the Society’s endorsement of content in any way.