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Frits R Mooi - One of the best experts on this subject based on the ideXlab platform.
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laboratory diagnosis of Pertussis
Clinical Microbiology Reviews, 2015Co-Authors: Anneke Van Der Zee, J F P Schellekens, Frits R MooiAbstract:The introduction of vaccination in the 1950s significantly reduced the morbidity and mortality of Pertussis. However, since the 1990s, a resurgence of Pertussis has been observed in vaccinated populations, and a number of causes have been proposed for this phenomenon, including improved diagnostics, increased awareness, waning immunity, and pathogen adaptation. The resurgence of Pertussis highlights the importance of standardized, sensitive, and specific laboratory diagnoses, the lack of which is responsible for the large differences in Pertussis notifications between countries. Accurate laboratory diagnosis is also important for distinguishing between the several etiologic agents of Pertussis-like diseases, which involve both viruses and bacteria. If Pertussis is diagnosed in a timely manner, antibiotic treatment of the patient can mitigate the symptoms and prevent transmission. During an outbreak, timely diagnosis of Pertussis allows prophylactic treatment of infants too young to be (fully) vaccinated, for whom Pertussis is a severe, sometimes fatal disease. Finally, reliable diagnosis of Pertussis is required to reveal trends in the (age-specific) disease incidence, which may point to changes in vaccine efficacy, waning immunity, and the emergence of vaccine-adapted strains. Here we review current approaches to the diagnosis of Pertussis and discuss their limitations and strengths. In particular, we emphasize that the optimal diagnostic procedure depends on the stage of the disease, the age of the patient, and the vaccination status of the patient.
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Pertussis resurgence waning immunity and pathogen adaptation two sides of the same coin
Epidemiology and Infection, 2014Co-Authors: Frits R Mooi, N A T Van Der Maas, H E De MelkerAbstract:Pertussis or whooping cough has persisted and resurged in the face of vaccination and has become one of the most prevalent vaccine-preventable diseases in Western countries. The high circulation rate of Bordetella Pertussis poses a threat to infants that have not been (completely) vaccinated and for whom Pertussis is a severe, life-threatening, disease. The increase in Pertussis is mainly found in age groups in which immunity has waned and this has resulted in the perception that waning immunity is the main or exclusive cause for the resurgence of Pertussis. However, significant changes in B. Pertussis populations have been observed after the introduction of vaccinations, suggesting a role for pathogen adaptation in the persistence and resurgence of Pertussis. These changes include antigenic divergence with vaccine strains and increased production of Pertussis toxin. Antigenic divergence will affect both memory recall and the efficacy of antibodies, while higher levels of Pertussis toxin may increase suppression of the innate and acquired immune system. We propose these adaptations of B. Pertussis have decreased the period in which Pertussis vaccines are effective and thus enhanced the waning of immunity. We plead for a more integrated approach to the Pertussis problem which includes the characteristics of the vaccines, the B. Pertussis populations and the interaction between the two.
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bordetella Pertussis and vaccination the persistence of a genetically monomorphic pathogen
Infection Genetics and Evolution, 2010Co-Authors: Frits R MooiAbstract:Abstract Before childhood vaccination was introduced in the 1950s, Pertussis or whooping cough was a major cause of infant death worldwide. Widespread vaccination of children was successful in significantly reducing morbidity and mortality. However, despite vaccination, Pertussis has persisted and, in the 1990s, resurged in a number of countries with highly vaccinated populations. Indeed, Pertussis has become the most prevalent vaccine-preventable disease in developed countries with estimated infection frequencies of 1–6%. Recently vaccinated children are well protected against Pertussis disease and its increase is mainly seen in adolescents and adults in which disease symptoms are often mild. The etiologic agent of Pertussis, Bordetella Pertussis, is extremely monomorphic and its ability to persist in the face of intensive vaccination is intriguing. Numerous studies have shown that B. Pertussis populations changed after the introduction of vaccination suggesting adaptation. These adaptations did not involve the acquisition of novel genes but small genetic changes, mainly SNPs, and occurred in successive steps in a period of 40 years. The earliest adaptations resulted in antigenic divergence with vaccine strains. More recently, strains emerged with increased Pertussis toxin (Ptx) production. Here I argue that the resurgence of Pertussis is the compound effect of pathogen adaptation and waning immunity. I propose that the removal by vaccination of naive infants as the major source for transmission was the crucial event which has driven the changes in B. Pertussis populations. This has selected for strains which are more efficiently transmitted by primed hosts in which immunity has waned. The adaptation of B. Pertussis to primed hosts involved delaying an effective immune response by antigenic divergence with vaccine strains and by increasing immune suppression through higher levels of Ptx production. Higher levels of Ptx may also benefit transmission by enhancing clinical symptoms. The study of B. Pertussis populations has not only increased our understanding of pathogen evolution, but also suggests way to improve Pertussis vaccines, underlining the public health significance of population-based studies of pathogens.
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bordetella Pertussis strains with increased toxin production associated with Pertussis resurgence
Emerging Infectious Diseases, 2009Co-Authors: Frits R Mooi, Marjolein Van Gent, Qiushui He, Marieke J Bart, Kees Heuvelman, Sabine C De Greeff, Dimitri A Diavatopoulos, Peter Teunis, Nico J D Nagelkerke, Jussi MertsolaAbstract:Before childhood vaccination was introduced in the 1940s, Pertussis was a major cause of infant death worldwide. Widespread vaccination of children succeeded in reducing illness and death. In the 1990s, a resurgence of Pertussis was observed in a number of countries with highly vaccinated populations, and Pertussis has become the most prevalent vaccine-preventable disease in industrialized countries. We present evidence that in the Netherlands the dramatic increase in Pertussis is temporally associated with the emergence of Bordetella Pertussis strains carrying a novel allele for the Pertussis toxin promoter, which confers increased Pertussis toxin (Ptx) production. Epidemiologic data suggest that these strains are more virulent in humans. We discuss changes in the ecology of B. Pertussis that may have driven this adaptation. Our results underline the importance of Ptx in transmission, suggest that vaccination may select for increased virulence, and indicate ways to control Pertussis more effectively.
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bordetella Pertussis the causative agent of whooping cough evolved from a distinct human associated lineage of b bronchiseptica
PLOS Pathogens, 2005Co-Authors: Dimitri A Diavatopoulos, Craig Cummings, Leo M Schouls, Mary M Brinig, David A Relman, Frits R MooiAbstract:Bordetella Pertussis, B. bronchiseptica, B. paraPertussishu, and B. paraPertussisov are closely related respiratory pathogens that infect mammalian species. B. Pertussis and B. paraPertussishu are exclusively human pathogens and cause whooping cough, or Pertussis, a disease that has resurged despite vaccination. Although it most often infects animals, infrequently B. bronchiseptica is isolated from humans, and these infections are thought to be zoonotic. B. Pertussis and B. paraPertussishu are assumed to have evolved from a B. bronchiseptica–like ancestor independently. To determine the phylogenetic relationships among these species, housekeeping and virulence genes were sequenced, comparative genomic hybridizations were performed using DNA microarrays, and the distribution of insertion sequence elements was determined, using a collection of 132 strains. This multifaceted approach distinguished four complexes, representing B. Pertussis, B. paraPertussishu, and two distinct B. bronchiseptica subpopulations, designated complexes I and IV. Of the two B. bronchiseptica complexes, complex IV was more closely related to B. Pertussis. Of interest, while only 32% of the complex I strains were isolated from humans, 80% of the complex IV strains were human isolates. Comparative genomic hybridization analysis identified the absence of the Pertussis toxin locus and dermonecrotic toxin gene, as well as a polymorphic lipopolysaccharide biosynthesis locus, as associated with adaptation of complex IV strains to the human host. Lipopolysaccharide structural diversity among these strains was confirmed by gel electrophoresis. Thus, complex IV strains may comprise a human-associated lineage of B. bronchiseptica from which B. Pertussis evolved. These findings will facilitate the study of pathogen host-adaptation. Our results shed light on the origins of the disease Pertussis and suggest that the association of B. Pertussis with humans may be more ancient than previously assumed.
Kathleen Winter - One of the best experts on this subject based on the ideXlab platform.
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a population based study of recurrent symptomatic bordetella Pertussis infections in children in california 2010 2015
Clinical Infectious Diseases, 2017Co-Authors: Lauren Platt, Melissa Thun, Kathleen Harriman, Kathleen WinterAbstract:Background Natural infection with Bordetella Pertussis is thought to result in 4-20 years of immunity against subsequent symptomatic Pertussis infection. However, these estimates are based on studies in unvaccinated or whole-cell Pertussis-vaccinated children. We conducted a population-based study of Pertussis infection and reinfection during a 5-year period in California in an cohort vaccinated exclusively with acellular Pertussis (aP) vaccine. Methods California surveillance data were reviewed to identify all children with 2 reported incidents of Pertussis with symptom onset between 1 January 2010 and 31 December 2015. Case investigation reports were reviewed, and children with ≥2 episodes of symptomatic Pertussis infection that met the case definition were included. Results Of 26259 Pertussis cases reported in children (aged <18 years), 27 children met the inclusion criteria. Recurrent cases occurred among children of all ages; 5 (19%) were <6 months of age at the time of their first illness. The time from initial infection to reinfection was <1 year in 11 (41%) cases. Twenty-one children (78%) had received ≥3 doses of diphtheria and tetanus toxoids and aP vaccine at the time of their first Pertussis infection, 1 (4%) had received 1 dose, and 5 (19%) were unvaccinated. Conclusions Recurrent cases of Pertussis infection are extremely rare. Based on this surveillance data, approximately 0.1% of children who were infected with Pertussis experienced a clinically significant second episode of Pertussis within 4 years. More research is needed to understand the immune response to B. Pertussis infection in children vaccinated with aP vaccines.
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effectiveness of prenatal tetanus diphtheria and acellular Pertussis vaccination on Pertussis severity in infants
Clinical Infectious Diseases, 2017Co-Authors: James D. Cherry, Kathleen Winter, Kathleen HarrimanAbstract:Background All US women are recommended to receive a tetanus, diphtheria, and acellular Pertussis (Tdap) vaccine at 27-36 weeks gestation during each pregnancy to reduce the risk of Pertussis to their infants. The impact of this strategy on severity of disease among infected infants has not been evaluated. Methods We use a retrospective cohort study design evaluating whether Pertussis-infected infants born in 2011-2015 whose mothers received Tdap vaccine during pregnancy had less severe Pertussis, resulting in a lower risk of hospitalization or intensive care unit admission compared with infants born to unvaccinated mothers. Results Infected infants of vaccinated mothers were significantly less likely to be hospitalized and had significantly shorter hospital stays compared with infants born to unvaccinated mothers, after adjustment for chronological and gestational age and receipt of diphtheria and tetanus toxoids and acellular Pertussis vaccine. Unadjusted and adjusted vaccine effectiveness for preventing hospitalization among infants with Pertussis was 72% (95% confidence interval [CI], 49%-85%) and 58% (95% CI 15%-80%), respectively. No infants born to vaccinated mothers required intubation or died of Pertussis. Conclusions Infants with Pertussis whose mothers received Tdap during pregnancy had a significantly lower risk of hospitalization and intensive care unit admission and shorter hospital stays. Prenatal Tdap vaccination is a critical strategy for reducing the morbidity and mortality from Pertussis.
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california Pertussis epidemic 2010
The Journal of Pediatrics, 2012Co-Authors: Kathleen Winter, Kathleen Harriman, Jennifer Zipprich, Robert Schechter, John Talarico, James Watt, Gilberto ChavezAbstract:Objective In 2010, California experienced the highest number of Pertussis cases in >60 years, with >9000 cases, 809 hospitalizations, and 10 deaths. This report provides a descriptive epidemiologic analysis of this epidemic and describes public health mitigation strategies that were used, including expanded Pertussis vaccine recommendations. Study design Clinical and demographic information were evaluated for all Pertussis cases with onset from January 1, 2010, through December 31, 2010, and reported to the California Department of Public Health. Results Hispanic infants younger than 6 months had the highest disease rates; all deaths and most hospitalizations occurred in infants younger than 3 months. Most pediatric cases were vaccinated according to national recommendations, although 9% of those aged 6 months to 18 years were completely unvaccinated against Pertussis. High disease rates also were observed in fully vaccinated preadolescents, especially 10-year-olds. Mitigation strategies included expanded tetanus, diphtheria, and acellular Pertussis vaccine recommendations, public and provider education, distribution of free vaccine for postpartum women and contacts of infants, and clinical guidance on diagnosis and treatment of Pertussis in young infants. Conclusions Infants too young to be fully vaccinated against Pertussis remain at highest risk of severe disease and death. Data are needed to evaluate strategies offering direct protection of this vulnerable population, such as immunization of pregnant women and of newborns. The high rate of disease among preadolescents suggests waning of immunity from the diphtheria, tetanus, and acellular Pertussis series; additional studies are warranted to evaluate the efficacy and duration of protection of the diphtheria, tetanus, and acellular Pertussis series and the tetanus, diphtheria, and acellular Pertussis series.
Michael E Pichichero - One of the best experts on this subject based on the ideXlab platform.
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maternal immunization with tetanus diphtheria Pertussis vaccine effect on maternal and neonatal serum antibody levels
American Journal of Obstetrics and Gynecology, 2011Co-Authors: Stanley A. Gall, John Myers, Michael E PichicheroAbstract:Objective We sought to determine whether tetanus–diphtheria–Pertussis vaccination (Tdap) in pregnancy provides newborns antibodies against Pertussis when compared to mothers who did not receive Tdap. Study Design Paired maternal and umbilical cord blood samples were collected at the time of delivery and the serum stored at –86°C. For each paired sample of maternal and cord blood, the medical chart and vaccine history was reviewed to determine whether Tdap was received or not. Results Newborns born from mothers who received Tdap during pregnancy had significantly higher concentrations of diphtheria antitoxin ( P P = .004), and antibodies to Pertussis toxin ( P P = .002), pertactin ( P P P = .0141), Pertussis toxin ( P P = .0146). Conclusion Administering Tdap during pregnancy increases antibody titers against diphtheria and Pertussis antigens. Maternal Tdap may prevent neonatal Pertussis infection.
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acellular Pertussis vaccine booster combined with diphtheria and tetanus toxoids for adolescents
Pediatrics, 2006Co-Authors: Michael E Pichichero, Mark M Blatter, William A Kennedy, James Hedrick, Dominique Descamps, Leonard R FriedlandAbstract:Background The incidence of Pertussis is increasing, especially in adolescents, attributed in part to waning of immunity after childhood immunization. Recently licensed in the United States for use in adolescents, acellular Pertussis vaccines will provide an immunogenic and safe option for booster immunization against Pertussis. Methods This prospective, randomized, observer-blinded, multicenter, comparative study evaluated the safety and immunogenicity of a vaccine formulated with tetanus toxoid, reduced diphtheria toxoid, and acellular Pertussis antigens (Tdap) compared with tetanus and diphtheria toxoids vaccine (Td) for booster immunization in adolescents. There were 4114 healthy adolescents aged 10 to 18 years who completed childhood vaccination against diphtheria, tetanus, and Pertussis who were enrolled, randomized, and received study vaccine. Results Local and general symptoms were comparable between the Tdap and Td groups. The immune response of Tdap was comparable with Td vaccine for tetanus and diphtheria seroprotection and booster responses. In addition, geometric mean concentrations of antibody to Pertussis antigens, Pertussis toxoid, filamentous hemagglutinin, and pertactin exceeded the antibody response elicited after infant immunization with diphtheria and tetanus toxoids and acellular Pertussis antigens (DTaP) that had proven efficacy against Pertussis. Conclusions In adolescents, the studied Tdap was safe and immunogenic and induced Pertussis antibodies that were higher than those associated with efficacy in infants.
James D. Cherry - One of the best experts on this subject based on the ideXlab platform.
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effectiveness of prenatal tetanus diphtheria and acellular Pertussis vaccination on Pertussis severity in infants
Clinical Infectious Diseases, 2017Co-Authors: James D. Cherry, Kathleen Winter, Kathleen HarrimanAbstract:Background All US women are recommended to receive a tetanus, diphtheria, and acellular Pertussis (Tdap) vaccine at 27-36 weeks gestation during each pregnancy to reduce the risk of Pertussis to their infants. The impact of this strategy on severity of disease among infected infants has not been evaluated. Methods We use a retrospective cohort study design evaluating whether Pertussis-infected infants born in 2011-2015 whose mothers received Tdap vaccine during pregnancy had less severe Pertussis, resulting in a lower risk of hospitalization or intensive care unit admission compared with infants born to unvaccinated mothers. Results Infected infants of vaccinated mothers were significantly less likely to be hospitalized and had significantly shorter hospital stays compared with infants born to unvaccinated mothers, after adjustment for chronological and gestational age and receipt of diphtheria and tetanus toxoids and acellular Pertussis vaccine. Unadjusted and adjusted vaccine effectiveness for preventing hospitalization among infants with Pertussis was 72% (95% confidence interval [CI], 49%-85%) and 58% (95% CI 15%-80%), respectively. No infants born to vaccinated mothers required intubation or died of Pertussis. Conclusions Infants with Pertussis whose mothers received Tdap during pregnancy had a significantly lower risk of hospitalization and intensive care unit admission and shorter hospital stays. Prenatal Tdap vaccination is a critical strategy for reducing the morbidity and mortality from Pertussis.
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efficacy of an acellular Pertussis vaccine among adolescents and adults
The New England Journal of Medicine, 2005Co-Authors: Joel I Ward, James D. Cherry, Sweiju Chang, Susan Partridge, Hang Lee, John J Treanor, David P Greenberg, Wendy A Keitel, Stephen J Barenkamp, David I BernsteinAbstract:BACKGROUND Pertussis immunization of adults may be necessary to improve the control of a rising burden of disease and infection. This trial of an acellular Pertussis vaccine among adolescents and adults evaluated the incidence of Pertussis, vaccine safety, immunogenicity, and protective efficacy. METHODS Bordetella Pertussis infections and illnesses were prospectively assessed in 2781 healthy subjects between the ages of 15 and 65 years who were enrolled in a national multicenter, randomized, double-blind trial of an acellular Pertussis vaccine. Subjects received either a dose of a tricomponent acellular Pertussis vaccine or a hepatitis A vaccine (control) and were monitored for 2.5 years for illnesses with cough that lasted for more than 5 days. Each illness was evaluated with use of a nasopharyngeal aspirate for culture and polymerase-chain-reaction assay, and serum samples from patients in both acute and convalescent stages of illness were analyzed for changes in antibodies to nine B. Pertussis antigens. RESULTS Of the 2781 subjects, 1391 received the acellular Pertussis vaccine and 1390 received the control vaccine. The groups had similar ages and demographic characteristics, and the median duration of follow-up was 22 months. The acellular Pertussis vaccine was safe and immunogenic. There were 2672 prolonged illnesses with cough, but the incidence of this nonspecific outcome did not vary between the groups, even when stratified according to age, season, and duration of cough. On the basis of the primary Pertussis case definition, vaccine protection was 92 percent (95 percent confidence interval, 32 to 99 percent). Among unimmunized controls with illness, 0.7 percent to 5.7 percent had B. Pertussis infection, and the percentage increased with the duration of cough. On the basis of other case definitions, the incidence of Pertussis in the controls ranged from 370 to 450 cases per 100,000 person-years. CONCLUSIONS The acellular Pertussis vaccine was protective among adolescents and adults, and its routine use might reduce the overall disease burden and transmission to children.
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the epidemiology of Pertussis a comparison of the epidemiology of the disease Pertussis with the epidemiology of bordetella Pertussis infection
Pediatrics, 2005Co-Authors: James D. CherryAbstract:In the prevaccine era Pertussis epidemics followed a cyclic pattern, with peaks every 2 to 5 years. With the marked reduction of Pertussis by vaccination, the same cyclic pattern still occurs. Studies relating to reported Pertussis and Bordetella Pertussis infection have been reviewed and analyzed. The increase in reported Pertussis over the last 2 decades is mainly due to a greater awareness of Pertussis and perhaps to the use of several less efficacious vaccines. Studies of prolonged cough illnesses in adolescents and adults reveal that 13% to 20% are a result of B Pertussis infection. Serologic studies suggest that the rate of B Pertussis infection in adolescents and adults is ∼2.0% per year. The rate of cough illnesses (Pertussis) caused by B Pertussis infection in adolescents and adults is between 370 and 1500 per 100 000 population. These data suggest that there are between ∼800 000 and 3.3 million cases per year in the United States. The coming availability of adolescent- and adult-formulated diphtheria and tetanus toxoids and acellular Pertussis vaccines for adolescents and adults and their widespread use should reduce the reservoir of B Pertussis disease. It is suggested that a universal program of adolescent and adult boosters would decrease the circulation of B Pertussis in these age groups and possibly could lead to the elimination of the organism from the population.
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serologic response and antibody titer decay in adults with Pertussis
Clinical Infectious Diseases, 2004Co-Authors: Ulrich Heininger, James D. Cherry, Klemens StehrAbstract:Pertussis is a frequent and significant illness in adults. Because acellular Pertussis vaccines for use in adolescents and adults have now been developed, it is important to compare serologic responses in adults after infection with serologic responses in adults after vaccination. We measured IgG and IgA antibodies to 4 Bordetella Pertussis antigens at approximately 6-month intervals for 28 months in 11 adults with Pertussis. After reaching peak levels, titers of antibody to Pertussis toxin decreased more than did titers of antibodies to filamentous hemagglutinin, pertactin, and fimbriae type 1 and type 2. Although studies of adults who have been vaccinated with acellular Pertussis vaccines have had shorter follow-up periods than studies of adults with Pertussis infection, the antibody decay patterns are similar in both groups.
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antibody responses to bordetella Pertussis antigens and clinical correlations in elderly community residents
Clinical Infectious Diseases, 2000Co-Authors: Sally L Hodder, James D. Cherry, Edward A Mortimer, Amasa B Ford, Jeffrey Gornbein, Klara K PappAbstract:A serological study to determine the frequency of Bordetella Pertussis infection in 100 adults aged >/=65 years was carried out over a 3-year period. Ten serum samples (collected every 4 months) from each subject were examined for IgA and IgG antibodies to the following B. Pertussis antigens: Pertussis toxin (PT), filamentous hemagglutinin (FHA), pertactin, and fimbriae-2. A >/=2-fold titer increase in ELISA units from one time period to the next was considered serological evidence of infection. The rate of serologically defined infection (i.e., in which there was an increase in titer against any antigen) was 19.7 per 100 person-years. With the use of more specific criteria that indicate definite B. Pertussis infection (>/=2-fold increase in titer to PT) and probable B. Pertussis infection (>/=2-fold increase in titer to PT or >/=2-fold increase to fimbriae-2), the rates were 3.3 and 8.0 per 100 person-years, respectively. Fifty percent of individuals with definite B. Pertussis infections had time-associated symptomatology. Antibody patterns over time suggest that antibody to FHA and perhaps to pertactin is stimulated by infections with other organisms, as well as B. Pertussis infections. Our data suggest that symptomatic Pertussis occurs in elderly individuals. Consideration should be given to immunization of the elderly with acellular Pertussis vaccines.
Mary Ramsay - One of the best experts on this subject based on the ideXlab platform.
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a case control study to estimate the effectiveness of maternal Pertussis vaccination in protecting newborn infants in england and wales 2012 2013
Clinical Infectious Diseases, 2015Co-Authors: Gavin Dabrera, Norman K. Fry, Gayatri Amirthalingam, Nick Andrews, Helen Campbell, Sonia Ribeiro, Edna Kara, Mary RamsayAbstract:Background Infants with Pertussis infection are at risk of severe clinical illness and death. Several countries, including the United Kingdom, have introduced maternal Pertussis vaccination during pregnancy to protect infants from infection following national increases in Pertussis notifications. The objective of this study was to estimate the effectiveness of maternal Pertussis vaccination in protecting infants against laboratory-confirmed Pertussis infection. Methods A case-control study was undertaken in England and Wales between October 2012 and July 2013. Cases were infants aged Results Mothers of 10 cases (17%) and 39 controls (71%) received Pertussis vaccine in pregnancy. This gave an unadjusted VE of 91% (95% confidence interval [CI], 77%-97%). Adjusted VE was 93% (95% CI, 81%-97%). Conclusions Maternal Pertussis vaccination is effective in preventing Pertussis infection in infants aged
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a case control study to estimate the effectiveness of maternal Pertussis vaccination in protecting newborn infants in england and wales 2012 2013
Clinical Infectious Diseases, 2015Co-Authors: Gavin Dabrera, Gayatri Amirthalingam, Nick Andrews, Helen Campbell, Sonia Ribeiro, Edna Kara, Mary RamsayAbstract:BACKGROUND: Infants with Pertussis infection are at risk of severe clinical illness and death. Several countries, including the United Kingdom, have introduced maternal Pertussis vaccination during pregnancy to protect infants from infection following national increases in Pertussis notifications. The objective of this study was to estimate the effectiveness of maternal Pertussis vaccination in protecting infants against laboratory-confirmed Pertussis infection. METHODS: A case-control study was undertaken in England and Wales between October 2012 and July 2013. Cases were infants aged <8 weeks at onset with Pertussis infection tested by real-time polymerase chain reaction or culture. Family doctors of each case were asked to identify healthy infants born consecutively after the case in each practice, to act as controls. Fifty-eight cases and 55 controls were included in this study. Odds ratios (ORs) were calculated for the association between maternal vaccination and infant Pertussis infection. The vaccine effectiveness (VE) was calculated as 1 - OR. This was adjusted for sex, geographical region, and birth period. RESULTS: Mothers of 10 cases (17%) and 39 controls (71%) received Pertussis vaccine in pregnancy. This gave an unadjusted VE of 91% (95% confidence interval [CI], 77%-97%). Adjusted VE was 93% (95% CI, 81%-97%). CONCLUSIONS: Maternal Pertussis vaccination is effective in preventing Pertussis infection in infants aged <8 weeks and may be considered in other countries experiencing high levels of Pertussis notifications.
