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Prenatal Tdap vaccination prevents the occurrence of and reduces the severity of pertussis in infants, two retrospective cohort studies showed.
In 2012, the Advisory Committee on Immunization Practices recommended that pregnant women receive a Tdap vaccination during their third trimester of pregnancy to optimize the transfer of pertussis antibodies to the fetus. Since the committee’s recommendation, no studies to evaluate the effectiveness of this strategy have been conducted in the United States, Kathleen Winter of the California Department of Public Health and her associates reported (Clin. Infect. Dis. 2016. doi: 10.1093/cid/ciw634) .
Therefore, Ms. Winter and her associates conducted two separate retrospective cohort studies: one to compare the effectiveness of prenatal versus postpartum Tdap vaccination in preventing pertussis and the second to investigate the effectiveness of prenatal Tdap vaccination on pertussis severity in infants.
For the comparison study, researchers identified 42,941 mothers who were vaccinated during pregnancy and 31,563 mothers who were vaccinated following delivery. The stage of pregnancy at the time of vaccination was documented for 42,218 of the mothers vaccinated prenatally, and 77% were vaccinated during the recommended window of 27-36 weeks’ gestation. For the remaining mothers, 14% received vaccinations before 27 weeks’ gestation, and 9% were vaccinated after 36 weeks’ gestation. Infants whose mothers received the Tdap vaccine at any point during pregnancy were less likely to develop pertussis before 8 weeks of age (odds ratio, 0.36; 95% confidence interval, 0.15-0.89) or 12 weeks of age (OR, 0.47; 95% CI, 0.24-0.92).
Moreover, infants whose mothers received the vaccine during 27-36 weeks’ gestation were less likely to develop pertussis than were infants whose mothers were vaccinated during pregnancy but outside the 27- to 36-week time frame (OR, 0.22; 95% CI, 0.08-0.63).
Overall, Tdap vaccination during 27-36 weeks’ gestation was 85% more effective in reducing pertussis in infants younger than 8 weeks old and 72% more effective in preventing pertussis in infants younger than 12 weeks old, compared with postpartum vaccination.
In a companion paper, researchers described the results of a separate retrospective cohort study, the “first known study demonstrating that prenatal Tdap vaccination reduces severity of disease in infants who are infected with pertussis,” according to Ms. Winter and her associates (Clin. Infect. Dis. 2016. doi: 10.1093/cid/ciw633).
For this study, the researchers identified 420 infants born between January 2011 and December 2015 who reported with pertussis at less than 63 days of age and had known maternal vaccination status. Of those 420 infants, only 49 mothers (12%) received Tdap vaccination during pregnancy, and only 14 received Tdap during the recommended window of 27-36 weeks’ gestation.
Infants born to mothers who received the Tdap vaccine during pregnancy were significantly less likely to be hospitalized when they developed pertussis (OR, 0.4; 95% CI, 0.2-0.9), were less likely to be admitted to the intensive care unit (OR, 0.5; 95% CI, 0.2-1.2), and had shorter hospital stays (median, 3 days vs. 6 days; P = .019). Infants born to vaccinated mothers also were older when they developed pertussis and were less likely to display common pertussis symptoms: paroxysmal cough, apnea, cyanosis, and whoop.
“Prenatal Tdap vaccination was 58% effective in preventing hospitalizations in infants infected with pertussis,” the researchers wrote, adding that “prenatal Tdap vaccination of mothers is a critical strategy for reducing the morbidity and mortality from pertussis.”
On Twitter @jessnicolecraig
The two papers by Ms. Winter and her colleagues are remarkably important and of high clinical interest. In 2012, recognizing the significant morbidity and mortality of pertussis among infants in the first 2-3 months of life and the lack of a newborn vaccination for pertussis, the Advisory Committee on Immunization Practices (ACIP) recommended maternal vaccination at 27-36 weeks’ gestation to stem the tide of increasing pertussis infections in this vulnerable age group. The recommendation was based on immunogenicity studies that showed maternal vaccination at 27-36 weeks’ gestation boosted maternal antibodies to pertussis antigens in the acellular vaccines used and that the antibodies crossed the placenta in sufficient amounts such that protection in the newborn could be anticipated up to at least 3 months of age.
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Dr. Michael E. Pichichero |
Winter et al. showed in these two companion papers that the ACIP recommendation was effective and excellent results have been achieved in California. I would expect the same results across the United States.
While this research is novel in the United States, the results could have been anticipated because two prior studies from the United Kingdom and Australia demonstrated the effectiveness of maternal Tdap vaccination. Although the study design was retrospective (a weakness, compared with a prospective study design), the findings are convincing.
More vaccines are being studied for possible maternal use during pregnancy. The hesitation of the “unknown risks” of maternal vaccination slowly are disappearing as more success stories like this one provide confidence in terms of the lack of side effects and the substantial benefit.
Dr. Michael E. Pichichero is a clinical professor in the department of pediatrics at the University of Rochester (N.Y.), a research professor at the Rochester Institute of Technology, and the director of research at Rochester General Hospital Research Institute. Dr. Pichichero said he had no relevant financial disclosures.
The two papers by Ms. Winter and her colleagues are remarkably important and of high clinical interest. In 2012, recognizing the significant morbidity and mortality of pertussis among infants in the first 2-3 months of life and the lack of a newborn vaccination for pertussis, the Advisory Committee on Immunization Practices (ACIP) recommended maternal vaccination at 27-36 weeks’ gestation to stem the tide of increasing pertussis infections in this vulnerable age group. The recommendation was based on immunogenicity studies that showed maternal vaccination at 27-36 weeks’ gestation boosted maternal antibodies to pertussis antigens in the acellular vaccines used and that the antibodies crossed the placenta in sufficient amounts such that protection in the newborn could be anticipated up to at least 3 months of age.
|
Dr. Michael E. Pichichero |
Winter et al. showed in these two companion papers that the ACIP recommendation was effective and excellent results have been achieved in California. I would expect the same results across the United States.
While this research is novel in the United States, the results could have been anticipated because two prior studies from the United Kingdom and Australia demonstrated the effectiveness of maternal Tdap vaccination. Although the study design was retrospective (a weakness, compared with a prospective study design), the findings are convincing.
More vaccines are being studied for possible maternal use during pregnancy. The hesitation of the “unknown risks” of maternal vaccination slowly are disappearing as more success stories like this one provide confidence in terms of the lack of side effects and the substantial benefit.
Dr. Michael E. Pichichero is a clinical professor in the department of pediatrics at the University of Rochester (N.Y.), a research professor at the Rochester Institute of Technology, and the director of research at Rochester General Hospital Research Institute. Dr. Pichichero said he had no relevant financial disclosures.
The two papers by Ms. Winter and her colleagues are remarkably important and of high clinical interest. In 2012, recognizing the significant morbidity and mortality of pertussis among infants in the first 2-3 months of life and the lack of a newborn vaccination for pertussis, the Advisory Committee on Immunization Practices (ACIP) recommended maternal vaccination at 27-36 weeks’ gestation to stem the tide of increasing pertussis infections in this vulnerable age group. The recommendation was based on immunogenicity studies that showed maternal vaccination at 27-36 weeks’ gestation boosted maternal antibodies to pertussis antigens in the acellular vaccines used and that the antibodies crossed the placenta in sufficient amounts such that protection in the newborn could be anticipated up to at least 3 months of age.
|
Dr. Michael E. Pichichero |
Winter et al. showed in these two companion papers that the ACIP recommendation was effective and excellent results have been achieved in California. I would expect the same results across the United States.
While this research is novel in the United States, the results could have been anticipated because two prior studies from the United Kingdom and Australia demonstrated the effectiveness of maternal Tdap vaccination. Although the study design was retrospective (a weakness, compared with a prospective study design), the findings are convincing.
More vaccines are being studied for possible maternal use during pregnancy. The hesitation of the “unknown risks” of maternal vaccination slowly are disappearing as more success stories like this one provide confidence in terms of the lack of side effects and the substantial benefit.
Dr. Michael E. Pichichero is a clinical professor in the department of pediatrics at the University of Rochester (N.Y.), a research professor at the Rochester Institute of Technology, and the director of research at Rochester General Hospital Research Institute. Dr. Pichichero said he had no relevant financial disclosures.
Prenatal Tdap vaccination prevents the occurrence of and reduces the severity of pertussis in infants, two retrospective cohort studies showed.
In 2012, the Advisory Committee on Immunization Practices recommended that pregnant women receive a Tdap vaccination during their third trimester of pregnancy to optimize the transfer of pertussis antibodies to the fetus. Since the committee’s recommendation, no studies to evaluate the effectiveness of this strategy have been conducted in the United States, Kathleen Winter of the California Department of Public Health and her associates reported (Clin. Infect. Dis. 2016. doi: 10.1093/cid/ciw634) .
Therefore, Ms. Winter and her associates conducted two separate retrospective cohort studies: one to compare the effectiveness of prenatal versus postpartum Tdap vaccination in preventing pertussis and the second to investigate the effectiveness of prenatal Tdap vaccination on pertussis severity in infants.
For the comparison study, researchers identified 42,941 mothers who were vaccinated during pregnancy and 31,563 mothers who were vaccinated following delivery. The stage of pregnancy at the time of vaccination was documented for 42,218 of the mothers vaccinated prenatally, and 77% were vaccinated during the recommended window of 27-36 weeks’ gestation. For the remaining mothers, 14% received vaccinations before 27 weeks’ gestation, and 9% were vaccinated after 36 weeks’ gestation. Infants whose mothers received the Tdap vaccine at any point during pregnancy were less likely to develop pertussis before 8 weeks of age (odds ratio, 0.36; 95% confidence interval, 0.15-0.89) or 12 weeks of age (OR, 0.47; 95% CI, 0.24-0.92).
Moreover, infants whose mothers received the vaccine during 27-36 weeks’ gestation were less likely to develop pertussis than were infants whose mothers were vaccinated during pregnancy but outside the 27- to 36-week time frame (OR, 0.22; 95% CI, 0.08-0.63).
Overall, Tdap vaccination during 27-36 weeks’ gestation was 85% more effective in reducing pertussis in infants younger than 8 weeks old and 72% more effective in preventing pertussis in infants younger than 12 weeks old, compared with postpartum vaccination.
In a companion paper, researchers described the results of a separate retrospective cohort study, the “first known study demonstrating that prenatal Tdap vaccination reduces severity of disease in infants who are infected with pertussis,” according to Ms. Winter and her associates (Clin. Infect. Dis. 2016. doi: 10.1093/cid/ciw633).
For this study, the researchers identified 420 infants born between January 2011 and December 2015 who reported with pertussis at less than 63 days of age and had known maternal vaccination status. Of those 420 infants, only 49 mothers (12%) received Tdap vaccination during pregnancy, and only 14 received Tdap during the recommended window of 27-36 weeks’ gestation.
Infants born to mothers who received the Tdap vaccine during pregnancy were significantly less likely to be hospitalized when they developed pertussis (OR, 0.4; 95% CI, 0.2-0.9), were less likely to be admitted to the intensive care unit (OR, 0.5; 95% CI, 0.2-1.2), and had shorter hospital stays (median, 3 days vs. 6 days; P = .019). Infants born to vaccinated mothers also were older when they developed pertussis and were less likely to display common pertussis symptoms: paroxysmal cough, apnea, cyanosis, and whoop.
“Prenatal Tdap vaccination was 58% effective in preventing hospitalizations in infants infected with pertussis,” the researchers wrote, adding that “prenatal Tdap vaccination of mothers is a critical strategy for reducing the morbidity and mortality from pertussis.”
On Twitter @jessnicolecraig
Prenatal Tdap vaccination prevents the occurrence of and reduces the severity of pertussis in infants, two retrospective cohort studies showed.
In 2012, the Advisory Committee on Immunization Practices recommended that pregnant women receive a Tdap vaccination during their third trimester of pregnancy to optimize the transfer of pertussis antibodies to the fetus. Since the committee’s recommendation, no studies to evaluate the effectiveness of this strategy have been conducted in the United States, Kathleen Winter of the California Department of Public Health and her associates reported (Clin. Infect. Dis. 2016. doi: 10.1093/cid/ciw634) .
Therefore, Ms. Winter and her associates conducted two separate retrospective cohort studies: one to compare the effectiveness of prenatal versus postpartum Tdap vaccination in preventing pertussis and the second to investigate the effectiveness of prenatal Tdap vaccination on pertussis severity in infants.
For the comparison study, researchers identified 42,941 mothers who were vaccinated during pregnancy and 31,563 mothers who were vaccinated following delivery. The stage of pregnancy at the time of vaccination was documented for 42,218 of the mothers vaccinated prenatally, and 77% were vaccinated during the recommended window of 27-36 weeks’ gestation. For the remaining mothers, 14% received vaccinations before 27 weeks’ gestation, and 9% were vaccinated after 36 weeks’ gestation. Infants whose mothers received the Tdap vaccine at any point during pregnancy were less likely to develop pertussis before 8 weeks of age (odds ratio, 0.36; 95% confidence interval, 0.15-0.89) or 12 weeks of age (OR, 0.47; 95% CI, 0.24-0.92).
Moreover, infants whose mothers received the vaccine during 27-36 weeks’ gestation were less likely to develop pertussis than were infants whose mothers were vaccinated during pregnancy but outside the 27- to 36-week time frame (OR, 0.22; 95% CI, 0.08-0.63).
Overall, Tdap vaccination during 27-36 weeks’ gestation was 85% more effective in reducing pertussis in infants younger than 8 weeks old and 72% more effective in preventing pertussis in infants younger than 12 weeks old, compared with postpartum vaccination.
In a companion paper, researchers described the results of a separate retrospective cohort study, the “first known study demonstrating that prenatal Tdap vaccination reduces severity of disease in infants who are infected with pertussis,” according to Ms. Winter and her associates (Clin. Infect. Dis. 2016. doi: 10.1093/cid/ciw633).
For this study, the researchers identified 420 infants born between January 2011 and December 2015 who reported with pertussis at less than 63 days of age and had known maternal vaccination status. Of those 420 infants, only 49 mothers (12%) received Tdap vaccination during pregnancy, and only 14 received Tdap during the recommended window of 27-36 weeks’ gestation.
Infants born to mothers who received the Tdap vaccine during pregnancy were significantly less likely to be hospitalized when they developed pertussis (OR, 0.4; 95% CI, 0.2-0.9), were less likely to be admitted to the intensive care unit (OR, 0.5; 95% CI, 0.2-1.2), and had shorter hospital stays (median, 3 days vs. 6 days; P = .019). Infants born to vaccinated mothers also were older when they developed pertussis and were less likely to display common pertussis symptoms: paroxysmal cough, apnea, cyanosis, and whoop.
“Prenatal Tdap vaccination was 58% effective in preventing hospitalizations in infants infected with pertussis,” the researchers wrote, adding that “prenatal Tdap vaccination of mothers is a critical strategy for reducing the morbidity and mortality from pertussis.”
On Twitter @jessnicolecraig
FROM CLINICAL INFECTIOUS DISEASES
Key clinical point: Prenatal Tdap vaccination prevents the occurrence of and reduces the severity of pertussis in infants.
Major finding: Tdap vaccination during 27-36 weeks’ gestation was 85% more effective in reducing pertussis in infants younger than 8 weeks old, compared with postpartum Tdap vaccination.
Data source: Two retrospective cohort studies.
Disclosures: The California Department of Public Health Immunization Branch funded this study. One investigator reported receiving financial compensation from GlaxoSmithKline and serving as a speaker for Sanofi Pasteur.
