Infants aged <1 year are at highest risk for pertussis-related morbidity and mortality. In 2012, Tdap (tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis) vaccine was recommended for ...women during each pregnancy to protect infants in the first months of life; data on effectiveness of this strategy are currently limited.
We conducted a case-control evaluation among pertussis cases <2 months old with cough onset between 1 January 2011 and 31 December 2014 from 6 US Emerging Infection Program Network states. Controls were hospital-matched and selected by birth certificate. Mothers were interviewed to collect information on demographics, household characteristics, and healthcare providers. Provider-verified immunization history was obtained on mothers and infants. Mothers were considered vaccinated during pregnancy if Tdap was received ≥14 days before delivery; trimester was calculated using Tdap date, infant's date of birth, and gestational age. Odds ratios were calculated using multivariable conditional logistic regression; vaccine effectiveness (VE) was estimated as (1 - odds ratio) × 100%.
A total of 240 cases and 535 controls were included; 17 (7.1%) case mothers and 90 (16.8%) control mothers received Tdap during the third trimester of pregnancy. The multivariable VE estimate for Tdap administered during the third trimester of pregnancy was 77.7% (95% confidence interval CI, 48.3%-90.4%); VE increased to 90.5% (95% CI, 65.2%-97.4%) against hospitalized cases.
Vaccination during pregnancy is an effective way to protect infants during the early months of life. With a continuing resurgence in pertussis, efforts should focus on maximizing Tdap uptake among pregnant women.
Pertussis is poorly controlled, with the highest rates of morbidity and mortality among infants. Although the source of infant pertussis is often unknown, when identified, mothers have historically ...been the most common reservoir of transmission. Despite high vaccination coverage, disease incidence has been increasing. We examined whether infant source of infection (SOI) has changed in the United States in light of the changing epidemiology.
Cases <1 year old were identified at Enhanced Pertussis Surveillance sites between January 1, 2006 to December 31, 2013. SOI was collected during patient interview and was defined as a suspected pertussis case in contact with the infant case 7 to 20 days before infant cough onset.
A total of 1306 infant cases were identified; 24.2% were <2 months old. An SOI was identified for 569 cases. Infants 0 to 1 months old were more likely to have an SOI identified than 2- to 11-month-olds (54.1% vs 40.2%, respectively; P < .0001). More than 66% of SOIs were immediate family members, most commonly siblings (35.5%), mothers (20.6%), and fathers (10.0%); mothers predominated until the transition to siblings beginning in 2008. Overall, the SOI median age was 14 years (range: 0-74 years); median age for sibling SOIs was 8 years.
In contrast to previous studies, our data suggest that the most common source of transmission to infants is now siblings. While continued monitoring of SOIs will optimize pertussis prevention strategies, recommendations for vaccination during pregnancy should directly increase protection of infants, regardless of SOI.
Background Most current evidence on risk factors for hospitalization because of coronavirus disease 2019 (COVID-19) comes from studies using data abstracted primarily from electronic health records, ...limited to specific populations, or that fail to capture over-the-counter medications and adjust for potential confounding factors. Properly understanding risk factors for hospitalization will help improve clinical management and facilitate targeted prevention messaging and forecasting and prioritization of clinical and public health resource needs. Objectives To identify risk factors for hospitalization using patient questionnaires and chart abstraction. Methods We randomly selected 600 of 1,738 laboratory-confirmed Colorado COVID-19 cases with known hospitalization status and illness onset during March 9-31, 2020. In April 2020, we collected demographics, social history, and medications taken in the 30 days before illness onset via telephone questionnaire and collected underlying medical conditions in patient questionnaires and medical record abstraction. Results Overall, 364 patients participated; 128 were hospitalized and 236 were non-hospitalized. In multivariable analysis, chronic hypoxemic respiratory failure with oxygen requirement (adjusted odds ratio aOR 14.64; 95% confidence interval CI 1.45-147.93), taking opioids (aOR 8.05; CI 1.16-55.77), metabolic syndrome (aOR 5.71; CI 1.18-27.54), obesity (aOR 3.35; CI 1.58-7.09), age greater than or equal to65 years (aOR 3.22; CI 1.20-7.97), hypertension (aOR 3.14; CI 1.47-6.71), arrhythmia (aOR 2.95; CI 1.00-8.68), and male sex (aOR 2.65; CI 1.44-4.88), were significantly associated with hospitalization. Conclusion We identified patient characteristics, medications, and medical conditions, including some novel ones, associated with hospitalization. These data can be used to inform clinical and public health resource needs.
The appropriate use of clinically accurate diagnostic tests is essential for the detection of pertussis, a poorly controlled vaccine-preventable disease. The purpose of this study was to estimate the ...sensitivity and specificity of different diagnostic criteria including culture, multi-target polymerase chain reaction (PCR), anti-pertussis toxin IgG (IgG-PT) serology, and the use of a clinical case definition. An additional objective was to describe the optimal timing of specimen collection for the various tests.
Clinical specimens were collected from patients with cough illness at seven locations across the United States between 2007 and 2011. Nasopharyngeal and blood specimens were collected from each patient during the enrollment visit. Patients who had been coughing for ≤ 2 weeks were asked to return in 2-4 weeks for collection of a second, convalescent blood specimen. Sensitivity and specificity of each diagnostic test were estimated using three methods-pertussis culture as the "gold standard," composite reference standard analysis (CRS), and latent class analysis (LCA).
Overall, 868 patients were enrolled and 13.6% were B. pertussis positive by at least one diagnostic test. In a sample of 545 participants with non-missing data on all four diagnostic criteria, culture was 64.0% sensitive, PCR was 90.6% sensitive, and both were 100% specific by LCA. CRS and LCA methods increased the sensitivity estimates for convalescent serology and the clinical case definition over the culture-based estimates. Culture and PCR were most sensitive when performed during the first two weeks of cough; serology was optimally sensitive after the second week of cough.
Timing of specimen collection in relation to onset of illness should be considered when ordering diagnostic tests for pertussis. Consideration should be given to including IgG-PT serology as a confirmatory test in the Council of State and Territorial Epidemiologists (CSTE) case definition for pertussis.
Summary Background Routine infant immunisation with seven-valent pneumococcal conjugate vaccine (PCV7) began in the USA in 2000. Although invasive pneumococcal disease has declined substantially, the ...programme's effect on hospital admissions for pneumonia is unknown. We therefore assessed the effect of the programme on rates of all-cause and pneumococcal pneumonia admissions. Methods Data from the Nationwide Inpatient Sample, the largest inpatient database available in the USA, were analysed with an interrupted time-series analysis that used pneumonia (all-cause and pneumococcal) admission rates as the main outcomes. Monthly admission rates estimated for years after the introduction of PCV7 vaccination (2001–2004) were compared with expected rates calculated from pre-PCV7 years (1997–1999). The year of vaccine introduction (2000) was excluded, and rates of admission for dehydration were assessed for comparison. Findings At the end of 2004, all-cause pneumonia admission rates had declined by 39% (95% CI 22–52) for children younger than 2 years, who were the target population of the vaccination programme. This annual decline in all-cause pneumonia admissions of 506 (291–675) per 100 000 children younger than 2 years represented about 41 000 pneumonia admissions prevented in 2004. During the 8 study years, 10 659 (2%) children younger than 2 years admitted with pneumonia were coded as having pneumococcal disease; these rates declined by 65% (47–77). This decline represented about 17 fewer admissions per 100 000 children in 2004. Admission rates for dehydration for children younger than 2 years remained stable over the study period. Interpretation The reduction in all-cause pneumonia admissions in children younger than 2 years provides an estimate of the proportion of childhood pneumonias attributable to Streptococcus pneumoniae in the USA that are vaccine preventable. Our results contribute to the growing body of evidence supporting the beneficial effects of the pneumococcal conjugate vaccines in children.
Data on the duration of detectable Zika virus-specific IgM in infected persons are limited. Neutralizing antibody cross-reactivity occurs between Zika virus and related flaviviruses, but the degree ...to which this confounds diagnosis is uncertain. We tested serum specimens collected 12-19 months after illness onset from patients with confirmed Zika virus disease for Zika virus IgM and Zika virus and dengue virus neutralizing antibodies. Among 62 participants, 45 (73%) had detectable Zika virus IgM and 12 (19%) had an equivocal result. Although all patients tested had Zika virus neutralizing antibodies, 39 (63%) also had neutralizing antibodies against dengue virus; of those, 12 (19%) had <4-fold difference between Zika virus and dengue virus titers, and 5 (8%) had dengue virus titer >4-fold higher than Zika virus titer. Prolonged detection of IgM and neutralizing antibody cross-reactivity make it difficult to determine the timing of Zika virus infection and differentiate between related flaviviruses.
Acellular pertussis vaccines replaced whole-cell vaccines for the 5-dose childhood vaccination series in 1997. A sixth dose of pertussis-containing vaccine, tetanus toxoid, reduced diphtheria toxoid, ...and acellular pertussis, adsorbed (Tdap), was recommended in 2005 for adolescents and adults. Studies examining Tdap vaccine effectiveness (VE) among adolescents who have received all acellular vaccines are limited.
To assess Tdap VE and duration of protection, we conducted a matched case-control study during the 2012 pertussis epidemic in Washington among adolescents born during 1993-2000. All pertussis cases reported from January 1 through June 30, 2012, in 7 counties were included; 3 controls were matched by primary provider clinic and birth year to each case. Vaccination histories were obtained through medical records, the state immunization registry, and parent interviews. Participants were classified by type of pertussis vaccine received on the basis of birth year: a mix of whole-cell and acellular vaccines (1993-1997) or all acellular vaccines (1998-2000). We used conditional logistic regression to calculate odds ratios comparing Tdap receipt between cases and controls.
Among adolescents who received all acellular vaccines (450 cases, 1246 controls), overall Tdap VE was 63.9% (95% confidence interval CI: 50% to 74%). VE within 1 year of vaccination was 73% (95% CI: 60% to 82%). At 2 to 4 years postvaccination, VE declined to 34% (95% CI: -0.03% to 58%).
Tdap protection wanes within 2 to 4 years. Lack of long-term protection after vaccination is likely contributing to increases in pertussis among adolescents.
In 2010, California experienced its largest pertussis epidemic in more than 60 years; a substantial burden of disease was noted in the 7- to 10-year-old age group despite high diphtheria, tetanus, ...and acellular pertussis vaccine (DTaP) coverage, indicating the possibility of waning protection.
To evaluate the association between pertussis and receipt of 5 DTaP doses by time since fifth DTaP dose.
Case-control evaluation conducted in 15 California counties. Cases (n = 682) were all suspected, probable, and confirmed pertussis cases among children aged 4 to 10 years reported from January through December 14, 2010; controls (n = 2016) were children in the same age group who received care from the clinicians reporting the cases. Three controls were selected per case. Vaccination histories were obtained from medical records and immunization registries.
Primary outcomes were (1) odds ratios (ORs) for the association between pertussis and receipt of the 5-dose DTaP series and (2) ORs for the association between pertussis and time since completion (<12, 12-23, 24-35, 36-47, 48-59, or ≥60 months) of the 5-dose DTaP series. Logistic regression was used to calculate ORs, accounting for clustering by county and clinician, and vaccine effectiveness (VE) was estimated as (1 - OR) × 100%.
Among cases and controls, 53 (7.8%) and 19 (0.9%) had not received any pertussis-containing vaccines, respectively. Compared with controls, children with pertussis had a lower odds of having received all 5 doses of DTaP (OR, 0.11; 95% CI, 0.06-0.21 estimated VE, 88.7%; 95% CI, 79.4%-93.8%). When children were categorized by time since completion of the DTaP series, using an unvaccinated reference group, children with pertussis compared with controls were less likely to have received their fifth dose within the prior 12 months (19 2.8% vs 354 17.6%, respectively; OR, 0.02; 95% CI, 0.01-0.04 estimated VE, 98.1%; 95% CI, 96.1%-99.1%). This association was evident with longer time since vaccination, with ORs increasing with time since the fifth dose. At 60 months or longer (n = 231 cases 33.9% and n = 288 controls 14.3%), the OR was 0.29 (95% CI, 0.15-0.54 estimated VE, 71.2%; 95% CI, 45.8%-84.8%). Accordingly, the estimated VE declined each year after receipt of the fifth dose of DTaP.
Among children in 15 California counties, children with pertussis, compared with controls, had lower odds of having received the 5-dose DTaP series; as time since last DTaP dose increased, the odds increased, which is consistent with a progressive decrease in estimated vaccine effectiveness each year after the final dose of pertussis vaccine.
In the United States, the proportion of Bordetella pertussis isolates lacking pertactin, a component of acellular pertussis vaccines, increased from 14% in 2010 to 85% in 2012. The impact on vaccine ...effectiveness (VE) is unknown.
We conducted 2 matched case-control evaluations in Vermont to assess VE of the 5-dose diphtheria, tetanus, and acellular pertussis vaccine (DTaP) series among 4- to 10-year-olds, and tetanus, diphtheria, and acellular pertussis vaccine (Tdap) among 11- to 19-year-olds. Cases reported during 2011 to 2013 were included. Three controls were matched to each case by medical home, and additionally by birth year for the Tdap evaluation. Vaccination history was obtained from medical records and parent interviews. Odds ratios (OR) were calculated by using conditional logistic regression; VE was estimated as (1-OR) × 100%. Pertactin status was determined for cases with available isolates.
Overall DTaP VE was 84% (95% confidence interval CI 58%-94%). VE within 12 months of dose 5 was 90% (95% CI 71%-97%), declining to 68% (95% CI 10%-88%) by 5-7 years post-vaccination. Overall Tdap VE was 70% (95% CI 54%-81%). Within 12 months of Tdap vaccination, VE was 76% (95% CI 60%-85%), declining to 56% (95% CI 16%-77%) by 2-4 years post-vaccination. Of cases with available isolates, >90% were pertactin-deficient.
Our DTaP and Tdap VE estimates remain similar to those found in other settings, despite high prevalence of pertactin deficiency in Vermont, suggesting these vaccines continue to be protective against reported pertussis disease.
As of March 2021, three COVID-19 vaccines had been authorized by the U.S. Food and Drug Administration (FDA) for use in the United States. Each has substantial efficacy in preventing COVID-19. ...However, as efficacy from trials was <100% for all three vaccines, disease in vaccinated people is expected to occur. We created a spreadsheet-based tool to estimate the number of symptomatic COVID-19 cases among vaccinated people (vaccine breakthrough infections) based on published vaccine efficacy (VE) data, percent of the population that has been fully vaccinated, and average number of COVID-19 cases reported per day. We estimate that approximately 199,000 symptomatic vaccine breakthrough infections (95% CI: ~183,000-214,000 cases) occurred in the United States during January-July 2021 among >156 million fully vaccinated people. With high SARS-CoV-2 transmission and increasing numbers of people vaccinated in the United States, vaccine breakthrough infections will continue to accumulate. Understanding expectations regarding number of vaccine breakthrough infections enables accurate public health messaging to help ensure that the occurrence of such cases does not negatively affect vaccine perceptions, confidence, and uptake.
PDF
