Pertussis in Germany: regional differences in management and vaccination status of hospitalized cases

Economic burden of pertussis in children: A single-center analysis in Hangzhou, China

The "reemergence of pertussis" has elicited international concerns, occurring paradoxically amidst the expansion of immunization programs. This study was aimed to evaluate quantitatively the economic burden and identify the determinants that influence the cost associated with treating pertussis in Chinese children. We evaluated the economic burden by Chinese children diagnosed with pertussis at the Children's Hospital, Zhejiang University School of Medicine in 2022. Direct medical expenses and the utilization of medical resources attributed to pertussis were calculated. A generalized linear regression model was applied to analyze the determinants that were associated with the direct medical expenses among patients. Among the 1110 pertussis patients included in the study, 1060 were outpatients and 50 were inpatients. The average direct medical cost was ¥1878.70(i.e. $279.33). Living in urban areas (OR:1.27, p = .04), complications (OR:1.40, p < .001), hospitalization (OR:10.04, p < .001), and ≥ 3 medical visits (OR:3.71, p < .001) were associated with increased direct medical expenses. Having received four doses of the pertussis vaccine was associated with reduced direct medical expenses (OR:0.81, p = .04). This study underscores a substantial economic burden of pertussis in Hangzhou, with pronounced implications for patients residing in urban areas, experiencing complications, requiring hospitalization, having multiple medical consultations, or lacking comprehensive pertussis vaccination.

Immunity against vaccine-preventable diseases among pregnant employees in Germany. A situation analysis before the introduction of the Measles Protection Act

BACKGROUND

Immunization against vaccine-preventable diseases prior to pregnancy is an important measure of primary prevention both for the mother and the unborn child. We analyzed immunity rates against measles, mumps, rubella, varicella, and pertussis in pregnant employees in Germany prior to significant changes in legal conditions in 2020, to provide a basis of comparison for future research.

METHODS

We analyzed occupational-medical routine data in three collectives of pregnant women with an occupational risk of infection in the years 2018 and 2019: 1: hospital staff with regular access to an in-house company physician (n = 148); 2: employees in childcare with regular access to external occupational-health services (n = 139); 3: teachers with no regular access to occupational healthcare (n = 285). Immune status was assessed by a physician based on vaccination certificates, laboratory results, and medical documentation on prior infections. We compared immunity rates against measles, rubella, varicella, and pertussis as well as full immunity against all targeted vaccine-preventable diseases.

RESULTS

Altogether, n = 572 pregnant women were included in our study. Of these women, 96.5 % were immune to rubella, 95.8 % to varicella, 88.3 % to measles, 82.7 % to mumps, and 67.8 % to pertussis. Only 56.2 % of the women had full immunity against all targeted vaccine-preventable diseases. Collective 1 showed the highest immunity rates against measles and pertussis as well as the highest rate of full immunity against all targeted vaccine-preventable diseases. The immunity rates against rubella and varicella did not differ significantly between the collectives. With the exception of rubella, the lowest immunity rates during pregnancy were found in Collective 3.

CONCLUSION

We found pregnancy-relevant immunity gaps in all our study groups with significant differences between the collectives. Considering the potentially devastating consequences of infections during pregnancy, all medical professionals and health-policy makers should be involved in an increased effort to improve vaccination rates prior to pregnancy.

The pertussis hypothesis: Bordetella pertussis colonization in the etiology of asthma and diseases of allergic sensitization

Decades of peer reviewed evidence demonstrate that: 1)Bordetellapertussisand pertussis toxin are potent adjuvants, inducing asthma and allergic sensitization in animal models of human disease, 2)Bordetella pertussisoften colonizes the human nasopharynx, and is well documented in highly pertussis-vaccinated populations and 3) in children, a history of whooping cough increases the risk of asthma and allergic sensitization disease. We build on these observations with six case studies and offer a pertussis-based explanation for the rapid rise in allergic disease in former East Germany following the fall of the Berlin Wall; the current asthma, peanut allergy, and anaphylaxis epidemics in the United States; the correlation between the risk of asthma and gross national income per capita by country; the lower risk of asthma and allergy in children raised on farms; and the reduced risk of atopy with increased family size and later sibling birth order. To organize the evidence for the pertussis hypothesis, we apply the Bradford Hill criteria to the association between Bordetella pertussisand asthma and allergicsensitization disease. We propose that, contrary to conventional wisdom that nasopharyngealBordetella pertussiscolonizing infections are harmless, subclinicalBordetella pertussiscolonization is an important cause of asthma and diseases of allergic sensitization.

Epidemiology and economic burden of measles, mumps, pertussis, and varicella in Germany: a systematic review

OBJECTIVES

Despite the availability of vaccines and the existence of public vaccination recommendations, outbreaks of vaccine-preventable childhood diseases still cause public health debate. The objective of this systematic review was to provide an overview of the current epidemiology and economic burden of measles, mumps, pertussis, and varicella in Germany.

METHODS

We systematically reviewed studies published since 2000. The literature search was conducted using PubMed and EMBASE. Also, we used German notification data to give an up-to-date overview of the epidemiology of the four diseases under consideration.

RESULTS

Thirty-six studies were included in our review. Results suggest that there is still considerable morbidity due to childhood diseases in Germany. Studies providing cost estimates are scarce. Comparative analyses of different data sources (notification data vs. claims data) revealed a potential underestimation of incidence estimates when using notification data. Furthermore, several studies showed regional differences in incidence of some of the diseases under consideration.

CONCLUSIONS

Our findings underline the need for improved vaccination and communication strategies targeting all susceptible age and risk groups on a national and local level.

Surveillance of hospitalized and outpatient cases of pertussis in Catalonia from 2003 to 2009

Pertussis is a vaccine-preventable disease that generates a large number of cases and hospitalizations. In Catalonia, the vaccination schedule includes three doses of vaccine at 2, 4 and 6 mo and two booster doses at 18 mo and 4-6 y. In 2002, DTPw was replaced by DTPa. The aim of this study was to determine how the vaccination status affects pertussis hospitalizations. Cases were obtained from the epidemiological surveillance system of the Generalitat of Catalonia from 2003 to 2009. Hospitalization, immunization status and type of vaccine received in reported cases were analyzed. OR and 95% confidence intervals (CI) were calculated. To control the effect of age (< 6 mo and ≥ 6 mo) Mantel-Haenszel OR (ORMH) were calculated; statistical significance was established as p < 0.05. During the study period, 1538 cases were reported. Cases below vaccination age (< 2 mo) were excluded. A total of 265 cases were hospitalized: 137 (51.7%) had no vaccine administrated, 104 (39.2%) were correctly vaccinated according to age and 24 (9.1%) were poorly vaccinated. Correct vaccination protected against hospitalization (ORMH: 0.33; 95%CI: 0.23-0.47). Of hospitalized cases, 38 (14.3%) had received DTPw and 91 (34.2%) DTPa. Both vaccines were effective in avoiding hospitalization, and comparison showed no differences (ORMH: 0.73; 95%CI: 0.46-1.14). We highlight the importance of a correct follow-up immunization schedule in reducing the number of cases and hospitalizations.

Acellular pertussis vaccine at birth and one month induces antibody responses by two months of age

BACKGROUND

Infants less than 3 months of age are at highest risk of hospitalization and death from pertussis. Several studies have examined antibody responses to pertussis vaccines at birth but no previous study has evaluated 2 doses of monovalent acellular pertussis vaccine (aPV) before 2 months of age.

METHODS

Seventy-six newborns were randomized at birth to 3 groups-aPV at birth and 1 month, aPV at birth, and control. All infants received hepatitis B vaccine (HBV) at birth followed at 2, 4, and 6 months by a combination vaccine including aPV, diphtheria, tetanus, Haemophilus influenzae type b (Hib), hepatitis B, polio antigens and 7 valent conjugate pneumococcal vaccine. IgG antibody responses to pertussis toxoid (PT), filamentous hemagglutinin (FHA), and pertactin (PRN) were measured in maternal serum and in infants at 2, 4, 6, and 8 months of age. Antibody responses to hepatitis B, diphtheria, tetanus, and Hib were measured at 8 months only. A parental diary and active telephone follow-up occurred for 7 days after each vaccination.

RESULTS

The aPV birth dose was well tolerated. By 2 months of age, 22 of 25 (88%) of 2 dose recipients had detectable IgG antibody to PT (IgG PT) compared with 9 of 21 (43%) who received a birth dose only and 3 of 20 (15%) of controls. Infants in the 2 dose group had a geometric mean concentration (GMC) of IgG PT of 16 ELISA units per mL (EU/mL), 95% CI: 11 to 25, significantly higher than birth dose only (5 EU/mL, 95% CI: 3-8) and controls (3 EU/mL, 95% CI: 2-5). At 8 months of age, following 5, 4, and 3 doses of aP-containing vaccine, respectively, IgG PT had plateaued but IgG to FHA and PRN increased with successive doses. There was a trend to lower antibody responses for hepatitis B and Hib with higher numbers of Pa doses.

CONCLUSION

These data suggest that aPV at birth and 1 month induces significantly higher IgG antibody against pertussis antigens by 2 months of age without reducing subsequent pertussis antibody responses. Larger and more detailed studies of aPV from birth are needed to evaluate other antibody responses and the potential of this approach to reduce death and morbidity from Bordetella pertussis infection in the first 3 months of life.

The epidemiology of pertussis in Germany: past and present

BACKGROUND

Current and past pertussis epidemiology in the two parts of Germany is compared in the context of different histories of vaccination recommendations and coverage to better understand patterns of disease transmission.

METHODS

Available regional pertussis surveillance and vaccination coverage data, supplemented by a literature search for published surveys as well as official national hospital and mortality statistics, were analyzed in the context of respective vaccination recommendations from 1964 onwards.

RESULTS

Routine childhood pertussis vaccination was recommended in the German Democratic Republic (GDR) from 1964 and in former West German states (FWG) from 1969, but withdrawn from 1974-1991 in FWG. Pertussis incidence declined to <1 case/100,000 inhabitants in GDR prior to reunification in 1991, while in FWG, where pertussis was not notifiable after 1961, incidence was estimated at 160-180 cases/100,000 inhabitants in the 1970s-1980s. Despite recommendations for universal childhood immunization in 1991, vaccination coverage decreased in former East German States (FEG) and increased only slowly in FWG. After introduction of acellular pertussis vaccines in 1995, vaccination coverage increased markedly among younger children, but remains low in adolescents, especially in FWG, despite introduction of a booster vaccination for 9-17 year olds in 2000. Reported pertussis incidence increased in FEG to 39.3 cases/100,000 inhabitants in 2007, with the proportion of adults increasing from 20% in 1995 to 68% in 2007. From 2004-2007, incidence was highest among 5-14 year-old children, with a high proportion fully vaccinated according to official recommendations, which did not include a preschool booster until 2006. Hospital discharge statistics revealed a ~2-fold higher pertussis morbidity among infants in FWG than FEG.

CONCLUSION

The shift in pertussis morbidity to older age groups observed in FEG is similar to reports from other countries with longstanding vaccination programs and suggests that additional booster vaccination may be necessary beyond adolescence. The high proportion of fully vaccinated cases in older children in FEG suggests waning immunity 5-10 years after primary immunisation in infancy. The higher incidence of pertussis hospitalisations in infants suggests a stronger force of infection in FWG than FEG. Nationwide pertussis reporting is required for better evaluation of transmission patterns and vaccination policy in both parts of Germany.

Pertussis: review of epidemiology, diagnosis, management and prevention

Bordetella pertussis--the cause of pertussis or whooping cough--is an exclusively human pathogen. Disease elimination by vaccination should, therefore, be possible, but has proved elusive. Many industrialised countries with long established immunisation programs are currently seeing a resurgence of pertussis, despite universal vaccination with high uptake, with the highest burden in the least immunised age groups (infants under 6 months of age and persons over 10 years old). However, low recognition and reporting and insensitive diagnostic tests mean that the true burden of pertussis is still underestimated. Recently, efforts to improve diagnostic yield include the expanded use of polymerase chain reaction and serological tests but both have significant limitations. The range of antibiotics available for treatment and prophylaxis has expanded to include the newer macrolides, azithromycin and clarithromycin, and a range of universal and targeted vaccination strategies have been implemented or proposed. This paper reviews the current epidemiology of pertussis in developed countries, including modes of clinical presentation, diagnosis, management and potential vaccination strategies.

Health burden of pertussis in infants and children

In countries with high rates of vaccination against pertussis, the incidence of this disease has decreased dramatically compared with the prevaccine era. However, pertussis still occurs in these countries, and severe morbidity and mortality are greatest among infants, particularly those who are unimmunized or incompletely immunized. Pertussis in older children and adults is perceived by many as being a mild disease, but it is a significant health burden in persons of all ages. Infants with pertussis experience the highest rates of hospitalization, complications and death. Severe complications include pneumonia, encephalopathy and meningoencephalitis. In addition, infants may experience weight loss, bronchitis, otitis media, apnea, cyanosis, inguinal hernia and rectal prolapse. It is essential to explore methods to prevent disease transmission to infants in the months before they complete their primary immunization series. The Global Pertussis Initiative was established to assess the true health burden of pertussis in infants and to suggest strategies to combat transmission and infection with Bordetella pertussis, which remains a significant public health concern.

Diagnosis and management of pertussis

Pertussis is increasing in frequency among children too young to be vaccinated and among adolescents and adults. This increase is due mainly to waning immunity among vaccinated individuals, who become susceptible during adolescence and adulthood and maintain the circulation of Bordetella pertussis. Infants are at highest risk of severe illness requiring hospital admission, complications and death. The clinical presentation in adolescents, adults and vaccinated individuals may be atypical, with paroxysmal cough of short duration or simply a persistent cough. Culture and polymerase chain reaction may be used to identify B. pertussis infection, but their sensitivity is high only in the early phase of the disease. Serologic tests are not standardized for the diagnosis of pertussis, and their clinical application is limited. Erythromycin is still considered in some countries to be the "gold standard" for therapy and prophylaxis; however, azithromycin and clarithromycin seem equally efficacious and are associated with fewer side effects.

[The resurgence of pertussis in developed countries: a problem for Brazil as well?]

Pertussis is currently considered an important public health problem in developed countries. In most of these countries, mass immunization for pertussis was initiated in the 1950s and was followed by a marked decrease in disease incidence. In the 1970s, pertussis was apparently under control in countries were vaccine coverage was maintained high. However, in the last two decades of the 20th century, the number of reported cases increased in all age groups, including adolescents and adults, indicating resurgence of the disease. This brief note aims to present the possible reasons for resurgence of this disease and to discuss the prospects of its future dynamics in Brazil. There has been no evidence to date for the resurgence of pertussis in Brazil. However, since mass immunization in Brazil began only in the 1980s, one cannot rule out the possibility that pertussis will resurge in the near future. Therefore, it is important that public health services closely monitor the epidemiological situation of pertussis in order, if necessary, to rapidly update the current immunization strategy.

Recommendations are needed for adolescent and adult pertussis immunisation: rationale and strategies for consideration

Pertussis vaccination of infants has dramatically reduced disease, complications and deaths in infancy and early childhood. But there is still a major public health challenge--to deal with the morbidity and economic burden of illness in older children, adolescents and adults. Furthermore, it is these groups that form a major source of infection for non-immunised and partially immunised infants who are at high risk of severe complications. Adult-type acellular pertussis vaccine confers safe and effective protection against pertussis. There are several strategies to consider for immunising older individuals. Universal vaccination of all age groups would be the best available strategy for protecting individuals. It would also reduce the potential for transmitting the disease to other susceptibles, particularly infants. However, such a policy may be difficult both logistically and economically at this time. More easily achievable as a first step would be a strategy of universal adolescent booster vaccination combined with a programme targeted at adults most likely to have contact with very young babies including healthcare and childcare workers, parents and close family contacts. There is also potential for offering vaccination to adults (and their carers and close contacts) whose medical conditions or advanced age may place them at increased risk of more severe pertussis disease. Specific details of immunisation programmes must be made on a country by country basis depending on local circumstances.