Rationale for pertussis booster vaccination throughout life in Europe

Attitude of Italian physicians toward pertussis diagnosis

Resurgence of pertussis has been observed in several countries whereas Italy continues to be a low incidence country. We hypothesize that the low reported incidence of pertussis in Italy could be biased by the attitude of physicians to suspect and diagnose pertussis in different age groups. We investigated the attitude of Italian physicians toward pertussis diagnosis through clinical scenarios. A cross-sectional study was conducted in June 2012 sending online questionnaires to pediatricians and general practitioners (GPs) involved in ambulatory primary care. The questionnaire included five clinical scenarios of patients of different ages (45 d, 5 y, 11 y, 24 y, 58 y) with prolonged cough of at least 2 weeks. Respondents were asked to choose a diagnosis among a list of 14. We observed a decreasing trend of suspected pertussis diagnosis with increasing age of the patient (from 46% at 45 d to 0 at 58 y). In Italy pertussis is seldom suspected in the differential diagnosis of cough particularly in adults. This may cause a significant under-notification of pertussis, with a higher impact in older age groups. Educational programs should be reinforced to consider the differential diagnosis of pertussis in individuals with atypical presentation and in older age groups.

Deciphering the impacts of vaccination and immunity on pertussis epidemiology in Thailand

Pertussis is a highly infectious respiratory disease that is currently responsible for nearly 300,000 annual deaths worldwide, primarily in infants in developing countries. Despite sustained high vaccine uptake, a resurgence in pertussis incidence has been reported in a number of countries. This resurgence has led to critical questions regarding the transmission impacts of vaccination and pertussis immunology. We analyzed pertussis incidence in Thailand--both age-stratified and longitudinal aggregate reports--over the past 30 y. To dissect the contributions of waning pertussis immunity and repeat infections to pertussis epidemiology in Thailand following a pronounced increase in vaccine uptake, we used likelihood-based statistical inference methods to evaluate the support for multiple competing transmission models. We found that, in contrast to other settings, there is no evidence for pertussis resurgence in Thailand, with each model examined pointing to a substantial rise in herd immunity over the past 30 y. Using a variety of empirical metrics, we verified our findings by documenting signatures of changing herd immunity over the study period. Importantly, this work leads to the conclusion that repeat infections have played little role in shaping pertussis epidemiology in Thailand. Our results are surprisingly emphatic in support of measurable impact of herd immunity given the uncertainty associated with pertussis epidemiology.

Pertussis re-emergence in the post-vaccination era

BACKGROUND

Resurgence of pertussis in the post-vaccination era has been reported in Western countries. A shift of cases from school-age children to adolescents, adults and children under 1 year of age has been described in the last decade, and mortality rates in infants are still sustained. We aimed to review and discuss the possible vaccination strategies which can be adopted in order to improve the pertussis control, by searches of Pubmed, and websites of US and European Centers for Disease Control and Prevention, between 1st January 2002, and 1st March 2013.

DISCUSSION

The following vaccination strategies have been retrieved and analysed: the cocooning strategy, the immunization of pregnant women and newborns, vaccination programs for preschool children, adolescents, adults and health-care workers. Cost-effectiveness studies provide some contrasting data, mainly supporting both maternal vaccination and cocooning. Adolescent and/or adult vaccination seems to be cost-effective, however data from observational studies suggest that this vaccination strategy, used alone, leads to a reduced pertussis burden globally, but does not affect the disease incidence in infants. Moreover, substantial logistical and economic difficulties have to be overcome to vaccinate the largest number of individuals.

SUMMARY

The simultaneous use of more than one strategy, including cocooning strategy plus vaccination of adolescents and adults, seems to be the most reasonable preventive measure. The development of new highly immunogenic and efficacious pertussis vaccines continues to be a primary objective for the control of pertussis.

Epidemiological and immunological reasons for pertussis vaccination in adolescents and adults

The resurgence of pertussis has been the subject of considerable debate. Hypotheses to explain increased reporting in developed countries have focused mainly on three aspects: (1) increased recognition of the disease in adolescents and adults; (2) waning of vaccine-induced immunity and (3) loss of vaccine efficacy due to an antigenic shift of Bordetella pertussis. Waning immunity after vaccination or natural infection combined with the absence of regular boosters either in the form of vaccine boosters or natural exposure to B. pertussis - due to the low circulation of the bacterium in well-immunized populations - has been suggested to explain this shift in the age distribution of pertussis. The highest incidence of the disease is currently reported among adolescents and adults who may additionally serve as the source of infection for susceptible infants. Immunological and epidemiological data indicates the need for a universal booster vaccination against pertussis for adolescents and adults.

The disease burden of pertussis in adults 50 years old and older in the United States: a retrospective study

Background

While the incidence of pertussis has increased in adolescents and adults in recent years in the U.S., little is known about the incidence and economic burden of pertussis in older adults. This study provides evidence of the incidence of pertussis and direct medical charges associated with pertussis episodes of care (PEOCs) in adults aged 50 years and older in the U.S.

Methods

PEOCs were divided into periods before and after the initial pertussis diagnosis was made (i.e., the index date) to capture any conditions immediately preceding the pertussis diagnosis that may have represented misdiagnoses and subsequent conditions that may have represented sequelae. Data were extracted from IMS's recently acquired SDI databases of longitudinal, patient-level practitioner claims and hospital operational billing records collected from private practitioners and hospitals, respectively, across the U.S. Patients 50 years and older with one or more ICD-9-CM diagnoses for pertussis/whooping cough and/or a laboratory test positive for Bordetella pertussis between 1/1/2006 and 10/31/2010 were eligible for study inclusion. Resource utilization and charges (i.e., unadjudicated claims) associated with the patient's physician and hospital care were analyzed. The nationally projected incidence of pertussis was estimated using a subsample of patients with the required data necessary for projection.

Results

Estimated incidence of diagnosed pertussis ranged from 2.1-4.6 cases per 100,000 people across the two age groups (50–64 and [greater than or equal to] 65) during the years 2006 to 2010. The analysis of charges included 5,748 patients [greater than or equal to] 50 years of age with pertussis. Average charges across the entire episode of care were $1,835 and $14,428 per patient in the outpatient and inpatient settings, respectively. The average number of outpatient (i.e., private practitioner) visits was 2 per patient in both the pre-index and post-index periods.

Conclusions

In the U.S., the incidence of diagnosed pertussis in adults 50 years and older has increased between 2006 and 2010. Healthcare utilization and charges associated with pertussis are substantial, suggesting the need for additional prevention and control strategies and a higher degree of clinical awareness on the part of health care providers. Additional research regarding pertussis in older populations is needed to substantiate these findings.

Detection of Bordetella pertussis from Clinical Samples by Culture and End-Point PCR in Malaysian Patients

Pertussis or whooping cough is a highly infectious respiratory disease caused by Bordetella pertussis. In vaccinating countries, infants, adolescents, and adults are relevant patients groups. A total of 707 clinical specimens were received from major hospitals in Malaysia in year 2011. These specimens were cultured on Regan-Lowe charcoal agar and subjected to end-point PCR, which amplified the repetitive insertion sequence IS481 and pertussis toxin promoter gene. Out of these specimens, 275 were positive: 4 by culture only, 6 by both end-point PCR and culture, and 265 by end-point PCR only. The majority of the positive cases were from ≤3 months old patients (77.1%) (P < 0.001). There was no significant association between type of samples collected and end-point PCR results (P > 0.05). Our study showed that the end-point PCR technique was able to pick up more positive cases compared to culture method.

Feasibility of a cocoon strategy for the prevention of pertussis in Italy: a survey of prevention department healthcare providers

A survey was proposed to Italian Prevention Department Directors to investigate the opinions on the value of the cocoon strategy and its introduction. Cocoon was considered the most efficacious strategy to protect newborns against pertussis by 76% of the interviewees. Prevention Departments should promote and coordinate locally the strategy in 75% of the respondents. Cocoon should be recommended by Regional Authority in 82% of the interviewees.

Pulsed-field gel electrophoresis analysis of Bordetella pertussis isolates circulating in Europe from 1998 to 2009

Between 1998 and 2009, Bordetella pertussis clinical isolates were collected during three periods, i.e., 1998 to 2001 (n = 102), 2004 to 2005 (n = 154), and 2007 to 2009 (n = 140), from nine countries with distinct vaccination programs, i.e., Denmark, Finland, France, Germany, The Netherlands, Norway, Poland, Sweden, and the United Kingdom. Pulsed-field gel electrophoresis (PFGE) analysis was performed according to standardized recommendations for epidemiological typing of B. pertussis. There were 81 different PFGE profiles, five of which (BpSR3, BpSR5, BpSR10, BpSR11, and BpSR12) were observed in 61% of the 396 isolates and shown to be predominant in almost all countries. The major profile, BpSR11, showed a decreasing trend from 25% to 30% in 1998 to 2005 to 13% in 2007 to 2009, and there were increases in BpSR3 and BpSR10 from 0% and 8% to 21% and 22%, respectively. One difference between these profiles is that BpSR11 contains isolates harboring the fim3-2 allele and BpSR3 and BpSR10 contain isolates harboring the fim3-1 allele. The total proportion of the five predominant profiles increased from 44% in 1998 to 2001 to 63% in 2004 to 2005 to 70% in 2007 to 2009. In conclusion, common PFGE profiles were identified in B. pertussis populations circulating in European countries with different vaccination programs and different vaccine coverages. These prevalent isolates contain the novel pertussis toxin promoter ptxP3 allele. However, there is evidence for diversifying selection between ptxP3 strains characterized by distinct PFGE profiles. This work shows that, even within a relatively short time span of 10 years, successful isolates which spread through Europe and cause large shifts in B. pertussis populations may emerge.

Self-boosting vaccines and their implications for herd immunity

Advances in vaccine technology over the past two centuries have facilitated far-reaching impact in the control of many infections, and today's emerging vaccines could likewise open new opportunities in the control of several diseases. Here we consider the potential, population-level effects of a particular class of emerging vaccines that use specific viral vectors to establish long-term, intermittent antigen presentation within a vaccinated host: in essence, "self-boosting" vaccines. In particular, we use mathematical models to explore the potential role of such vaccines in situations where current immunization raises only relatively short-lived protection. Vaccination programs in such cases are generally limited in their ability to raise lasting herd immunity. Moreover, in certain cases mass vaccination can have the counterproductive effect of allowing an increase in severe disease, through reducing opportunities for immunity to be boosted through natural exposure to infection. Such dynamics have been proposed, for example, in relation to pertussis and varicella-zoster virus. In this context we show how self-boosting vaccines could open qualitatively new opportunities, for example by broadening the effective duration of herd immunity that can be achieved with currently used immunogens. At intermediate rates of self-boosting, these vaccines also alleviate the potential counterproductive effects of mass vaccination, through compensating for losses in natural boosting. Importantly, however, we also show how sufficiently high boosting rates may introduce a new regime of unintended consequences, wherein the unvaccinated bear an increased disease burden. Finally, we discuss important caveats and data needs arising from this work.

Differences of IgG antibody avidity after an acellular pertussis (aP) booster in adolescents after a whole cell (wcP) or aP primary vaccination

Compared to whole cell pertussis (wcP) vaccines, acellular pertussis vaccines (aP) have a better safety profile with lower reactogenicity, although their short and long-term efficacy was found to be slightly lower. Up to now, no established serological parameter to predict long-term protection exists. IgG-anti-pertussis avidity possibly determines the effect of different pertussis vaccines and boosting intervals on long-term immunity. Thus, the avidity of a tetanus-diphtheria-aP booster at 10-14 years was tested in three groups of adolescents who had been previously immunized with either five doses of aP (5aP) at 2, 4, 6, 15-18 months and 5-6 years of age, four doses of aP (4aP) or four doses of wcP (4wcP) at 2, 4, 6 and 15-18 months of age. Relative avidity index (RAI) of IgG-anti-pertussis toxin (PT) and IgG-anti-filamentous-hemagglutinin (FHA) was assessed by an adapted ELISA. RAI of IgG-anti-PT and of IgG-anti-FHA correlated positively with antibody concentrations in the pre-vaccination and in the post-vaccination analysis and significantly increased after adolescent booster with aP in all groups. Pre- and post-vaccination, the proportion of participants with IgG-anti-PT RAI>40% (moderate to high avidity) was significantly lower in the 4wcP group (52.9% and 88.9%) compared to the 5aP group (89.5% and 100.0%). In conclusion, TdaP in adolescence induces an increase of antibody avidity and, thus, is able to enhance the binding-quality of antibodies against pertussis. The study suggests including antibody avidity into serological studies on the humoral response to provide information about the long-term efficacy of the vaccine.

Seroprevalence of pertussis in Senegal: a prospective study

BACKGROUND

Pertussis, also known as whooping cough, is a vaccine-preventable respiratory disease caused by Bordetella pertussis infection, against which Senegalese children are immunized with the diphtheria-tetanus-whole cell pertussis vaccine (DTwP). Seroepidemiology of pertussis has been widely described in industrialized countries, but rare are the studies referring to it in developing countries.

METHODS

We conducted a longitudinal survey in Northern Senegal to investigate the epidemiology of B. pertussis by evaluating the IgG antibody (Ab) response against pertussis toxin (PT). A cohort of 410 children aged 1 to 9 from five villages in the Middle Senegal River Valley were followed-up for 18 months. During that period, five visits were made to assess the immunological status of the children.

PRINCIPAL FINDINGS

PT-specific IgG responses were significantly different according to age. Until the age of 3, there was a decrease in the Ab response, which then increased in the older groups. Assessment of IgG antibodies to PT (IgG-PT) suggested evidence of recent exposures to the pathogen. Surprisingly, in one of the five villages the average Ab response to PT was very low at all ages during the first 6 months of the study. At the third visit, IgG-PT concentrations peaked to very high levels, to slightly decline at the end of the survey. This indicates an outbreak of B. pertussis, whereas in the other villages a pertussis endemic profile could be observed.

CONCLUSIONS

Pertussis is endemic in Northern Senegal despite the introduction of vaccination. The circulation of the bacteria seems to differ between geographic locations and over time. A more complete understanding of the epidemiology of pertussis and its environmental determinants could provide information to adapt vaccination programs.

T-cell responses before and after the fifth consecutive acellular pertussis vaccination in 4-year-old Dutch children

Immunization with acellular pertussis vaccine (aP) induces higher specific antibody levels and fewer adverse reactions than does immunization with the whole-cell vaccine (wP). However, antibody levels in infants induced by both types of pertussis vaccines wane already after 1 year. Therefore, long-term T-cell responses upon vaccination might play a role in protection against pertussis. In a cross-sectional study (ISRCTN65428640), we investigated T-helper (Th) cell immune responses in wP- or aP-vaccinated children before and after an aP low-dose or high-dose preschool booster at 4 years of age in The Netherlands. T cells were stimulated with pertussis vaccine antigens. The numbers of gamma interferon-producing cells and Th1, Th2, Th17, and interleukin-10 (IL-10) cytokine concentrations were determined. In addition, pertussis-specific IgE levels were measured in plasma. Children being vaccinated with aP vaccinations at 2, 3, 4, and 11 months of age still showed higher pertussis-specific T-cell responses at 4 years of age than did wP-vaccinated children. These T-cell responses failed to show a typical increase in cytokine production after a fifth aP vaccination but remained high after a low-dose booster and seemed to decline even after a high-dose booster. Importantly, elevated IgE levels were induced after this booster vaccination. In contrast, wP-vaccinated children had only low prebooster T-cell responses, and these children showed a clear postbooster T-cell memory response even after a low-dose booster vaccine. Four high-dose aP vaccinations in infancy induce high T-cell responses still present even 3 years after vaccination and enhanced IgE responses after preschool booster vaccination. Therefore, studies of changes in vaccine dosage, timing of pertussis (booster) vaccinations, and the possible association with local side effects are necessary.

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.

New insights into rotavirus vaccines

Rotavirus vaccines have shown to be effective and well tolerated in clinical trials. However it's crucial to point out that immunization occurs in "real-word" conditions different from ideal clinical trial settings. Thus, the impact of rotavirus vaccines in terms of effectiveness and safety needs to be evaluated in real-world conditions. Post-licensure data regarding vaccine impact, effectiveness and safety under routine use are now available and provide a "real-world view". We reviewed published data about the impact of rotavirus vaccines in the post-licensure era.

Pertussis in older adults: prospective study of risk factors and morbidity

BACKGROUND

There is limited information on the incidence, morbidity and risk factors for pertussis in adults, particularly those aged over 65 years.

METHODS

Population-based prospective cohort study of 263094 adults aged over 45 years (mean 62.8 years) recruited in the Australian state of New South Wales (the 45 and Up Study) between 2006 and 2008, and followed by record-linkage to laboratory-confirmed pertussis notifications, hospitalizations, and death records. The incidence of pertussis notifications and hospitalizations and relative risk (RR) of pertussis according to various participant characteristics was estimated using proportional hazards models.

RESULTS

Over a total follow-up of 217524 person-years, 205 adults had a pertussis notification and 12 were hospitalized; the incidence rate was 94 (95% confidence interval [CI], 82-108) and 5.5 (95% CI, 3.1-9.7) per 100000 person-years, respectively. The incidence of a pertussis notification did not differ by age but hospitalization rates progressively increased (2.2, 8.5, and 13.5 per 100000 person-years in age groups 45-64, 65-74, and 75+ years, respectively; P(trend) = .01). After adjusting for age, sex, and other factors, adults with a high body mass index (BMI; RR=1.52; 95% CI, 1.06-2.19 for BMI 30+kg/m(2) vs BMI <25 kg/m(2)) and with preexisting asthma (RR=1.64; 95% CI, 1.06-2.55 compared to those without asthma) were more likely to be notified.

CONCLUSIONS

Adults older than 65 years are more likely to be hospitalized for pertussis than those aged 45-64 years. Obesity and preexisting asthma were associated with a higher likelihood of pertussis notification. These findings suggest that pertussis vaccination would be particularly important for adults with these characteristics.

A randomised, double-blind, non-inferiority clinical trial on the safety and immunogenicity of a tetanus, diphtheria and monocomponent acellular pertussis (TdaP) vaccine in comparison to a tetanus and diphtheria (Td) vaccine when given as booster vaccinations to healthy adults

BACKGROUND

Increasing incidence of pertussis in adolescents and adults has stimulated the development of safe and immunogenic acellular pertussis vaccines for booster vaccination of adolescents and adults.

PURPOSE

To obtain clinical documentation of the safety and immunogenicity of a tetanus, diphtheria and monocomponent acellular pertussis combination vaccine (TdaP), when given as a booster vaccination to adults.

METHODS

The trial was double-blind, controlled and randomised. 802 healthy adults, aged 18-55 years who had completed childhood vaccination with diphtheria, tetanus and whole cell pertussis vaccine (DTwP), were booster vaccinated with TdaP or Td. Blood samples were taken before and one month after the vaccination for serological analysis and adverse events were recorded during the one-month-follow-up period.

RESULTS

The monocomponent acellular pertussis vaccine (aP) in the TdaP vaccine was immunogenic in adults with 92.0% of TdaP vaccinated subjects obtaining an anti-pertussis toxin (anti-PT) antibody booster response. TdaP was non-inferior to Td in eliciting seroprotective anti-tetanus and diphtheria antibody concentrations with more than 98% of subjects obtaining post-vaccination seroprotective concentrations (≥ 0.1 IU/mL). T and d booster response rates were 93.0% and 97.5%, respectively. The frequencies of solicited local adverse reactions were low and comparable between TdaP and Td vaccinees. In the TdaP group, 30.7% reported pain, 4.2% swelling and 2.0% erythema at the injection site. The most frequent solicited general symptoms were headache (20.4%), fatigue (17.0%) and myalgia (10.0%). In the Td group, 35.7% reported pain, 2.5% swelling and 3.2% erythema at the injection site, whereas headache, fatigue and myalgia were reported by 15.7%, 14.5% and 12.5%, respectively. In conclusion, TdaP Vaccine SSI was safe and immunogenic when given as a booster vaccination to adults.

Variation in adult vaccination policies across Europe: an overview from VENICE network on vaccine recommendations, funding and coverage

BACKGROUND

In 2010-2011, in the framework of the VENICE project, we surveyed European Union (EU) and Economic Area (EEA) countries to fill the gap of information regarding vaccination policies in adults. This project was carried out in collaboration with the United States National Vaccine Program Office, who conducted a similar survey in all developed countries.

METHODS

VENICE representatives of all 29 EU/EEA-countries received an online questionnaire including vaccination schedule, recommendations, funding and coverage in adults for 17 vaccine-preventable diseases.

RESULTS

The response rate was 100%. The definition of age threshold for adulthood for the purpose of vaccination ranged from 15 to 19 years (median=18 years). EU/EEA-countries recommend between 4 and 16 vaccines for adults (median=11 vaccines). Tetanus and diphtheria vaccines are recommended to all adults in 22 and 21 countries respectively. The other vaccines are mostly recommended to specific risk groups; recommendations for seasonal influenza and hepatitis B exist in all surveyed countries. Six countries have a comprehensive summary document or schedule describing all vaccines which are recommended for adults. None of the surveyed countries was able to provide coverage estimates for all the recommended adult vaccines.

CONCLUSIONS

Vaccination policies for adults are not consistent across Europe, including the meaning of "recommended vaccine" which is not comparable among countries. Coverage data for adults should be collected routinely like for children vaccination.

Shortened interval between tetanus vaccines

OBJECTIVE

To identify the minimum safe interval between tetanus-diphtheria (Td) and tetanus-diphtheria-acellular pertussis (Tdap) vaccines.

DATA SOURCES

Literature was retrieved through a review of ImmunoFacts, the Centers for Disease Control and Prevention (CDC) Web site, MEDLINE (1966-February 2012) and International Pharmaceutical Abstracts (1970-February 2012) using the terms Tdap, Td, and interval. In addition, reference citations from publications identified were reviewed.

STUDY SELECTION AND DATA EXTRACTION

All English-language articles identified from the data sources were evaluated. Studies addressing an interval of 2 years or less between Td and Tdap vaccines were included.

DATA SYNTHESIS

Two observational noninferiority studies have evaluated the safety of an interval of 2 years or less. The first involved a school-based immunization program to compare the safety of a single dose of Tdap given 18 months to 9 years after a tetanus and diphtheria toxoid-containing vaccine versus an interval of 10 or more years. Injection site erythema and swelling were increased among participants with shortened intervals between vaccines; however, no serious adverse events, entire limb swelling, or Arthus-like reactions were reported. The second study involved health care workers who received Tdap during a pertussis outbreak with the objective to compare safety of intervals less than 2 years between prior tetanus vaccination and Tdap with intervals 2 years or more. Criteria for noninferiority were met overall between the 2 intervals in terms of moderate and severe injection site reactions. Fever was more common with the shortened interval, as was any redness or any swelling. No serious adverse events were reported among the group with an interval of less than 2 years between vaccine administration.

CONCLUSIONS

Although well-designed randomized controlled trials are lacking, the current observational evidence and CDC provisional recommendations support a shortened interval between Td and Tdap vaccines to protect health care workers from pertussis. Intervals less than 2 years may be associated with an increased incidence of local injection site reactions.

Lessons learned and applied: what the 20th century vaccine experience can teach us about vaccines in the 21st century

Most vaccines available in the United States (US) have been incorporated into vaccination schedules for infants and young children, age groups particularly at risk of contracting infectious diseases. High universal vaccination coverage is responsible for substantially reducing or nearly eliminating many of the diseases that once killed thousands of children each year in the US.

Despite the success of infant vaccinations, periods of low vaccination coverage and the limited immunogenicity and duration of protection of certain vaccines have resulted in sporadic outbreaks, allowing some diseases to spread in communities. These challenges suggest that expanded vaccination coverage to younger infants and adolescents, and more immunogenic vaccines, may be needed in some instances.

This review focuses on the importance of infant immunization and explores the successes and challenges of current early childhood vaccination programs and how these lessons may be applied to other invasive diseases, such as meningococcal disease.

Pertussis: what the pediatric infectious disease specialist should know

Pertussis is a bacterial disease that is transmitted very efficiently from human to human by droplets. It occurs at any age, is endemic in any population, and can cause outbreaks in highly variable frequencies. Hallmark of the disease is cough with or without paroxysms, whoop, and vomiting. Diagnosis relies on clinical suspicion followed by laboratory confirmation (PCR, Serology) and should be followed by prompt antibiotic treatment to stop spread of the bacteria to contact persons. Control of pertussis by acellular vaccines is possible to some extent if immunization coverage is high and booster doses are given lifelong. However new vaccines with higher efficacy rates are warranted.

Vaccination recommendations for Germany

BACKGROUND

Vaccination is an effective means of preventing infectious diseases. In Germany, the Standing Vaccination Committee at the Robert Koch Institute (Ständige Impfkommission, STIKO) issues recommendations on vaccination to prevent the occurrence and spread of infectious diseases in the nation's population.

METHODS

Selective literature review, including consideration of the current STIKO recommendations.

RESULTS

The annually updated vaccination calendar currently includes recommendations for vaccination against diphtheria, tetanus, pertussis, type b Haemophilus influenzae, hepatitis B, poliomyelitis, and pneumococci, beginning at the age of eight weeks. From the age of twelve months onward, children should be vaccinated against measles, mumps, rubella, varicella, and serogroup C meningococci. In later childhood and adolescence, booster vaccinations are recommended, in addition to the provision of any vaccinations that may have been missed. Girls aged 12 to 17 years should be vaccinated against human papilloma virus. Adults should have their tetanus and diphtheria vaccinations refreshed regularly, and their pertussis vaccination refreshed once; from age 60 onward, they should be vaccinated against pneumococci and influenza.

CONCLUSIONS

The vaccinations recommended by the STIKO are available to all German citizens free of charge and provide effective protection against infectious disease.

Differences in the genomic content of Bordetella pertussis isolates before and after introduction of pertussis vaccines in four European countries

Resurgence of pertussis has been observed in many countries with high vaccination coverage and clonal expansion of certain Bordetella pertussis strains has been associated with recent epidemics in Europe. It is known that vaccinations have selected strains which are different from those used for vaccine production. However, little is known about the differences in genomic content of strains circulating before the vaccination was introduced. In this study, we compared the genomes of 39 vaccine strains and old clinical isolates (isolated 1941-1984) collected from Finland (n = 5), Poland (n = 14), Serbia (n = 10) and the UK (n = 10). The analysis included genotyping, pulsed-field gel electrophoresis (PFGE) and comparative genomic hybridisation (CGH). Compared to the strain Tohama I, the European isolates analyzed have lost three major regions of difference (RD3, 5 and 29). However, difference in frequency of the absent RDs 3 (BP0910A-BP0934), 5 (BP1135-BP1141) or 29 (BP1225) was observed among isolates from the four countries. Of the isolates with absent RD5, half had also a duplicated region in the genome. All four RDs (RD22 (BB0535-BB0541), 23 (BB0916-BB0921), 24 (BB1140-BB1158) and 26 (BB4880-BB4888)) absent in Tohama I were present in majority of the tested isolates. Results obtained from PFGE analysis correlated well with those of CGH. Recently a novel pertussis toxin promoter allele (ptxP3) was described. Isolates with ptxP3 have replaced resident ptxP1 isolates in the countries where this was investigated. When the recent isolates, collected in 2000-2004, selected from the four countries were examined, the ptxP3 allele was found in all countries except Poland. Our result indicates that at least three clusters of B. pertussis circulated in Europe in pre- and early vaccine era and their genomes were distinct from that of the reference strain Tohama I. Although progressive gene loss occurs in B. pertussis population with time, difference in frequency of the lost genes were observed among isolates from the four countries. The observed differences in genomic content might be vaccine-driven.