Coalition of advocates to vaccinate of Western European citizens aged 60 years and older

Adult vaccination against tetanus and diphtheria: the European perspective

Besides immunizations against influenza, Streptococcus pneumoniae and herpes zoster, which are recommended specifically for elderly people, regular booster vaccinations against tetanus, diphtheria and in some cases pertussis and polio are recommended in many European countries for adults, including elderly people. Vaccination recommendations for adults differ greatly between individual countries and coverage data is scarce. Tetanus-specific antibody concentrations are generally higher than diphtheria-specific antibodies, and a substantial proportion of adults, and particularly of elderly people, do not have protective antibody concentrations against diphtheria. Antibody levels increase upon booster vaccination in all age groups, but diphtheria-specific antibody concentrations remain below protective levels in some older individuals, even immediately after vaccination and long-term protection is frequently not achieved. Future vaccination strategies should therefore include regular and well-documented booster shots, e.g. against tetanus and diphtheria, throughout life.

Recall responses to tetanus and diphtheria vaccination are frequently insufficient in elderly persons

Demographic changes and a more active life-style in older age have contributed to an increasing public awareness of the need for lifelong vaccination. Currently many older persons have been vaccinated against selected pathogens during childhood but lack regular booster immunizations. The impact of regular vaccinations when started late in life was analyzed in an open, explorative trial by evaluating the immune response against tetanus and diphtheria in healthy older individuals. 252 persons aged above 60 years received a booster vaccination against tetanus, diphtheria, pertussis and polio and a subcohort (n=87) was recruited to receive a second booster vaccination against tetanus, diphtheria and pertussis 5 years later. The percentage of unprotected individuals at the time of enrollment differed substantially for tetanus (12%) and diphtheria (65%). Despite protective antibody concentrations 4 weeks after the first vaccination in almost all vaccinees, antibodies had again dropped below protective levels in 10% (tetanus) and 45% (diphtheria) of the cohort after 5 years. Protection was restored in almost all vaccinees after the second vaccination. No correlation between tetanus- and diphtheria-specific responses was observed, and antibody concentrations were not associated with age-related changes in the T cell repertoire, inflammatory parameters, or CMV-seropositivity suggesting that there was no general biological “non-responder type.” Post-vaccination antibody concentrations depended on pre-existing plasma cells and B cell memory as indicated by a strong positive relationship between post-vaccination antibodies and pre-vaccination antibodies as well as antibody-secreting cells. In contrast, antigen-specific T cell responses were not or only weakly associated with antibody concentrations. In conclusion, our findings demonstrate that single shot vaccinations against tetanus and/or diphtheria do not lead to long-lasting immunity in many elderly persons despite administration at relatively short intervals. Sufficient antigen-specific B cell memory B generated by adequate priming and consecutive booster vaccinations and/or exposure is a prerequisite for long-term protection.

Assessment of vaccine candidates for persons aged 50 and older: a review

BACKGROUND

The increasing life expectancy in most European countries has resulted in growth of the population 50 and older. This population is more susceptible to infectious diseases because of immunosenescence, co-morbidity and general frailty. Thus, to promote healthy aging, vaccination against vaccine-preventable-diseases could be one strategy. In addition to its possible individual benefits, vaccination may also yield social benefits, such as a lower overall cost of healthcare. Most European countries, however, offer only influenza vaccine although vaccines for pneumococcal disease, herpes zoster, pertussis, and hepatitis A are also available. Our aim is to review the knowledge of these vaccines for persons aged 50 and older and explore the arguments for expanding current vaccination programmes beyond just influenza.

METHODS

The evaluation model of Kimman et al. was used to assess herpes zoster, pneumococcal disease, pertussis and hepatitis A in terms of four domains: pathogen, vaccine, disease outcomes and cost-effectiveness. The sources were Dutch surveillance systems, seroprevalence studies and the international literature.

RESULTS

Herpes zoster, pneumococcal disease and pertussis are prevalent among persons aged 50 and older. Vaccines vary in effectiveness and have mild and self-limiting side effects. Vaccination against pneumococcal disease and pertussis causes adaptation of the responsible pathogen. For pertussis and hepatitis A, the vaccine is not registered specifically for the elderly population. Vaccination against herpes zoster and pertussis could improve quality of life, while vaccination against pneumococcal disease and hepatitis A prevents mortality. However, only vaccination against herpes zoster and pneumococcal disease appear to be cost-effective.

CONCLUSIONS

Vaccination can improve the health of the elderly population. As our review shows, however, the data are too incomplete to accurately judge its potential impact. More research is needed to determine how vaccination can most effectively improve the health of the growing population 50 years and older.

The importance of pertussis in older adults: a growing case for reviewing vaccination strategy in the elderly

Pertussis or whooping cough is increasingly being shown to be a respiratory infection affecting the elderly and a significant percentage of older people infected with Bordetella pertussis experience considerable morbidity and even mortality. However, current knowledge of burden of disease is limited largely to passive surveillance data with little well-designed active surveillance to better ascertain the true burden of pertussis in the elderly, to inform vaccination strategies. The current review aims to identify gaps in knowledge to inform policy considerations relating to pertussis vaccination among the elderly.

Promoting life course vaccination

Infectious diseases remain a significant cause of morbi-mortality in adults aged over 60 years, and many of these diseases are vaccine-preventable (VPDs). There is a pressing need to promote a lifelong vaccine schedule to increase vaccination against VPDs during the different stages of life. We outline the impact of vaccines on the burden of common infectious diseases and consider the negative clinical impact of VPDs in the unvaccinated population. We further illustrate that vaccine uptake is associated with a reduction in the burden of VPDs at any age of life, due to herd immunity. Disability-free and healthy aging is closely linked to childhood health and medical conditions in young adulthood. The midlife vaccine gap drastically impacts health in later life, especially in unvaccinated and older populations. These arguments underline the need for a preventive lifelong health perspective from childhood through old age.

Ensuring the willingness to vaccinate and be vaccinated

Vaccination is one of the success stories in modern day medicine and has contributed to a reduced burden of childhood diseases and increased longevity. However, adult vaccination has not achieved the same level of success and it is now thought that more adults die from vaccine-preventable diseases each year than children. Many of the reasons given by adults for not getting vaccinated are based upon ignorance of the true facts, lack of support/notification from the healthcare system or unfounded fears. The key to addressing these issues is improving communication and this needs to involve healthcare professionals and public health/social workers. To effect change we must provide motivating educational material, which ensures that the benefits of vaccination are clearly emphasized and that issues related to inconvenience and adverse events are discussed and put into perspective. Transparency is important and so the information must be complete and accurate. In addition, we need to make the immunization process easy and convenient for the patient (particularly for house-bound individuals and those who live some distance from a general practitioner) and it needs to be proactive (e-mails, reminders and recalls). Only through a massive commitment to making it work, with the lead taken by key healthcare managers/personnel, will we improve vaccine coverage and integrate vaccination of older adults into a life-long healthy aging strategy.

Improving the vaccination coverage of geriatric populations

Vaccination is an important component of disease prevention in the elderly; however, immunization coverage in this population is low. There is a clear need to improve vaccine coverage among this age group. To this end, various strategies can be employed. Raising awareness and improving the education of physicians and health care workers in the field of vaccination in geriatric populations play an important role. Active promotion of vaccination uptake should be implemented by health authorities and targeted to older adults. Other means, including the use of educational tools and guidelines to improve practice, should be more widely employed.

Willingness to vaccinate and to be vaccinated in adults

Vaccination may be mandated by regulation, as in some national infant vaccination programs, encouraged by health authorities, as in 'Flu vaccine campaigns for adults aged 60 years and older, or linked to the informed decision of individuals. Other methods include promotion by incentives to general practitioners, and recommendations from healthcare workers. All these factors contribute to variable vaccine coverage between countries and between different age and socio-economic groups. Many other factors, including providers' patient-oriented interventions and reimbursement issues play an important role in determining the level of vaccine uptake in a given population for a particular disease. However, the first step in vaccination campaigns is to give motivating information to healthcare workers that the benefits of being vaccinated outweigh possible inconvenience or adverse reactions. The information must be complete and accurate.When it has been ascertained that this information is understood and accepted, a system providing cheap and easy vaccination must be organised. Special groups such as the house-bound will need particular attention, appropriate information, and be included in free vaccination schemes. It should be acknowledged that social pressure often influences (positively or negatively) the decision of the individual. Lastly, a massive but objective information campaign is needed for the whole population, each and every visit to a health clinic being treated as an opportunity to check vaccination status and to vaccinate immediately if necessary. Simultaneous vaccination with two or more vaccines increases the chances of reaching the required population cover.