Changes in the Incidence of Invasive Bacterial Disease During the COVID-19 Pandemic in the United States, 2014-2020

BACKGROUND

Descriptions of changes in invasive bacterial disease (IBD) epidemiology during the coronavirus disease 2019 (COVID-19) pandemic in the United States are limited.

METHODS

We investigated changes in the incidence of IBD due to Streptococcus pneumoniae, Haemophilus influenzae, group A Streptococcus (GAS), and group B Streptococcus (GBS). We defined the COVID-19 pandemic period as 1 March to 31 December 2020. We compared observed IBD incidences during the pandemic to expected incidences, consistent with January 2014 to February 2020 trends. We conducted secondary analysis of a health care database to assess changes in testing by blood and cerebrospinal fluid (CSF) culture during the pandemic.

RESULTS

Compared with expected incidences, the observed incidences of IBD due to S. pneumoniae, H. influenzae, GAS, and GBS were 58%, 60%, 28%, and 12% lower during the pandemic period of 2020, respectively. Declines from expected incidences corresponded closely with implementation of COVID-19-associated nonpharmaceutical interventions (NPIs). Significant declines were observed across all age and race groups, and surveillance sites for S. pneumoniae and H. influenzae. Blood and CSF culture testing rates during the pandemic were comparable to previous years.

CONCLUSIONS

NPIs likely contributed to the decline in IBD incidence in the United States in 2020; observed declines were unlikely to be driven by reductions in testing.

High post-exposure prophylaxis (PEP) uptake among household contacts of pertussis patients enrolled in a PEP effectiveness evaluation - United States, 2015-2017

BACKGROUND

Post-exposure prophylaxis (PEP) for pertussis is recommended for household contacts of pertussis cases in the United States within 21 days of exposure, but data on PEP effectiveness for prevention of secondary cases in the setting of widespread pertussis vaccination are limited. We implemented a multi-state evaluation of azithromycin PEP use and effectiveness among household contacts.

METHODS

Culture- or PCR-confirmed pertussis cases were identified through surveillance. Household contacts were interviewed within 7 days of case report and again 14-21 days later. Interviewers collected information on exposure, demographics, vaccine history, prior pertussis diagnosis, underlying conditions, PEP receipt, pertussis symptoms, and pertussis testing. A subset of household contacts provided nasopharyngeal and blood specimens during interviews.

RESULTS

Of 299 household contacts who completed both interviews, 12 (4%) reported not receiving PEP. There was no evidence of higher prevalence of cough or pertussis symptoms among contacts who did not receive PEP. Of 168 household contacts who provided at least one nasopharyngeal specimen, four (2.4%) were culture or PCR positive for B. pertussis; three of these received PEP prior to their positive test result. Of 156 contacts with serologic results, 14 (9%) had blood specimens that were positive for IgG anti-pertussis toxin (PT) antibodies; all had received PEP.

CONCLUSIONS

Very high PEP uptake was observed among household contacts of pertussis patients. Although the number of contacts who did not receive PEP was small, there was no difference in prevalence of pertussis symptoms or positive laboratory results among these contacts compared with those who did receive PEP.

Changing Diagnostic Testing Practices for Foodborne Pathogens, Foodborne Diseases Active Surveillance Network, 2012-2019

BACKGROUND

Pathogen detection has changed with increased use of culture-independent diagnostic tests (CIDTs). CIDTs do not yield isolates, which are necessary to detect outbreaks using whole-genome sequencing. The Foodborne Diseases Active Surveillance Network (FoodNet) monitors clinical laboratory testing practices to improve interpretation of surveillance data and assess availability of isolates. We describe changes in practices over 8 years.

METHODS

During 2012-2019, 10 FoodNet sites collected standardized data about practices in clinical laboratories (range, 664-723 laboratories) for select enteric pathogens. We assessed changes in practices.

RESULTS

During 2012-2019, the percentage of laboratories that used only culture methods decreased, with the largest declines for Vibrio (99%-57%) and Yersinia (99%-60%). During 2019, the percentage of laboratories using only CIDTs was highest for Shiga toxin-producing Escherichia coli (43%), Campylobacter (34%), and Vibrio (34%). From 2015 to 2019, the percentage of laboratories that performed reflex culture after a positive CIDT decreased, with the largest declines for Shigella (75%-42%) and Salmonella (70%-38%). The percentage of laboratories that routinely submitted isolates to a public health laboratory decreased for all bacterial pathogens examined from 2015 to 2019.

CONCLUSIONS

By increasing use of CIDTs and decreasing reflex culture, clinical laboratories have transferred the burden of isolate recovery to public health laboratories. Until technologies allow for molecular subtyping directly from a patient specimen, state public health laboratories should consider updating enteric disease reporting requirements to include submission of isolates or specimens. Public health laboratories need resources for isolate recovery.

1299. Epidemiology of Invasive Pneumococcal Disease (IPD) in the United States 2011-2019

Background

Thirteen-valent pneumococcal conjugate vaccine (PCV13) was recommended for U.S. children aged < 5 years in February 2010 and recommended in series with 23-valent pneumococcal polysaccharide vaccine (PPSV23) for adults aged ≥ 65 years in 2014. PCV13 has led to dramatic reductions in invasive pneumococcal disease (IPD) burden. New, higher valency PCVs (PCV15, PCV20) are expected to be licensed for adults in late 2021. We examined remaining PCV13-type IPD among children and adults and assessed IPD burden potentially preventable through PCV15 and PCV20 use.

Methods

IPD cases (isolation of pneumococcus from sterile sites) were identified through CDC’s Active Bacterial Core surveillance during 1998–2019. Isolates were serotyped by Quellung or whole genome sequencing. Incidence rates (cases/100,000) were calculated using U.S. Census Bureau population denominators.

Results

After introduction of PCV13 in children, by 2013–2014, PCV13-type IPD declined 89% (from 15 to 2 cases/100,000) in children age < 5 years and 67% (from 19 to 7 cases/100,000) in adults age ≥ 65 years. During 2014–2019, rates of PCV13-type IPD in children and adults remained stable. In 2018–2019, among children age < 5 years, serotypes 3, 19F, 19A, and 6C accounted for most of the remaining PCV13-type IPD (46%, 32%, 14% and 4% respectively) (Figure 1). Among adults age ≥ 65 years, serotypes 3, 6C, 19A, and 19F accounted for most of the remaining PCV13-type IPD (62%, 12%, 10%, and 9% respectively) (Figure 1). During 2015–2019, rates of PCV15 and PCV20-type IPD have remained stable. In 2018–2019, among adults age ≥ 65 years, PCV15 non-PCV13-type IPD rates were 3.6 cases per 100,000 and accounted for 15% of all IPD. PCV20 non-PCV13-type IPD rates were 6.8 cases per 100,000 and accounted for 29% of all IPD (Figure 2). Among children age < 5 years, PCV15 non-PCV13-type IPD rates were 1.6 cases per 100,000 and accounted for 17% of all IPD. PCV20 non-PCV13-type IPD rates were 2.8 cases per 100,000 and accounted for 39% of all IPD (Figure 2).

Figure 1. Incidence rates of IPD among children < 5 years old, by pneumococcal conjugate vaccine type and individual PCV13 serotypes, 2011–2019

Conclusion

Following the dramatic reductions after PCV13 introduction, PCV13-type IPD has remained stable during the past five years. There are opportunities to prevent an additional 30% IPD burden among adults through new PCV use.

Disclosures

William Schaffner, MD, VBI Vaccines (Consultant) Lee Harrison, MD, GSK, Merck, Pfizer, Sanofi Pasteur (Consultant)

Racial disparities in invasive Haemophilus influenzae disease - United States, 2008-2017

BACKGROUND

Since the introduction of Haemophilus influenzae serotype b (Hib) conjugate vaccines in the United States, invasive H. influenzae disease (Hi) epidemiology has changed and racial disparities have not been recently described.

METHODS

Active population- and laboratory-based surveillance for Hi was conducted through Active Bacterial Core surveillance (ABCs) at 10 U.S. sites. Data from 2008-2017 was used to estimate projected nationwide annual incidence in cases/100,000.

RESULTS

During 2008-2017, ABCs identified 7379 Hi cases. Of 6705 (90.9%) patients with reported race, 76.2% were White, 18.6% were Black, 2.8% were Asian/Pacific Islander (PI), and 2.4% were American Indian and Alaska Native (AI/AN). Nationwide annual incidence was 1.8 cases/100,000. By race, incidence was highest among AI/AN populations (3.1) and lowest among Asian/PI populations (0.8). Nontypeable Hi (NTHi) caused the largest incidence within all races (1.3), with no striking disparities identified. Among AI/AN children aged <5 years, incidence of Hi serotype a (Hia) was 16.7 times higher and Hib incidence was 22.4 times higher than among White children. Though Hia incidence was lower among White and Black populations compared to AI/AN, Hia incidence increased 13.6% annually among White children and 40.4% annually among Black children aged <5 years.

CONCLUSIONS

While NTHi causes the largest Hi burden overall, AI/AN populations experience disproportionately high rates of Hia and Hib, with the greatest disparity among AI/AN children aged <5 years. Prevention tools are needed to reduce disparities affecting AI/AN children and address increasing Hia incidence in other communities.

Challenges in Surveillance for Streptococcal Toxic Shock Syndrome: Active Bacterial Core Surveillance, United States, 2014-2017

OBJECTIVES

Routine surveillance for streptococcal toxic shock syndrome (STSS), a severe manifestation of invasive group A Streptococcus (GAS) infections, likely underestimates its true incidence. The objective of our study was to evaluate routine identification of STSS in a national surveillance system for invasive GAS infections.

METHODS

Active Bacterial Core surveillance (ABCs) conducts active population-based surveillance for invasive GAS disease in selected US counties in 10 states. We categorized invasive GAS cases with a diagnosis of STSS made by a physician as STSS-physician and cases that met the Council of State and Territorial Epidemiologists (CSTE) clinical criteria for STSS based on data in the medical record as STSS-CSTE. We evaluated agreement between the 2 methods for identifying STSS and compared the estimated national incidence of STSS when applying proportions of STSS-CSTE and STSS-physician among invasive GAS cases from this study with national invasive GAS estimates for 2017.

RESULTS

During 2014-2017, of 7572 invasive GAS cases in ABCs, we identified 1094 (14.4%) as STSS-CSTE and 203 (2.7%) as STSS-physician, a 5.3-fold difference. Of 1094 STSS-CSTE cases, we identified only 132 (12.1%) as STSS-physician cases. Agreement between the 2 methods for identifying STSS was low (κ = 0.17; 95% CI, 0.14-0.19). Using ABCs data, we estimated 591 cases of STSS-physician and 3618 cases of STSS-CSTE occurred nationally in 2017.

CONCLUSIONS

We found a large difference in estimates of incidence of STSS when applying different surveillance methods and definitions. These results should help with better use of currently available surveillance data to estimate the incidence of STSS and to evaluate disease prevention efforts, in addition to guiding future surveillance efforts for STSS.

1474. Impact of 13-valent Pneumococcal Conjugate Vaccine (PCV13) on Non-bacteremic Pneumococcal Pneumonia (NBPP) among Adults in the United States, 2013-2017

Background

PCV13 was recommended for U.S. children in 2010 and for adults ≥ 65 years in 2014. Vaccine coverage among adults ≥ 65 years was 43% in 2017. We evaluated PCV13 impact on NBPP among adults.

Methods

NBPP cases (clinically or radiographically confirmed pneumonia and a positive pneumococcal urine antigen test (PUAT) in a hospitalized adult aged ≥ 18 years) were identified at select hospitals in 10 sites within CDC’s Active Bacterial Core surveillance during 2013-2017. NBPP rates (per 100,000) were estimated using U.S. Census Bureau population denominators and adjusted for the proportion of pneumonia patients tested by PUAT and the number of pneumonia admissions in the catchment area.

Results

Between 2013 and 2017, 4,430 NBPP cases were identified. Adults aged ≥ 65 years accounted for 49% of cases. Case fatality rate was 6%. From 2013 to 2014, rates of NBPP declined from 153 to 90 (41% reduction, 95%CI 28%, 51%) in ≥ 65 year-olds; 60 to 40 (34% reduction, 95%CI 22%, 45%) in 50-64 year-olds; and 15 to 10 (36% reduction, 95%CI 25%, 47%) in 18-49 year-olds. From 2014 to 2017, rates of NBPP increased in all ages, but remained below 2013 rates (Figure).

Figure. Estimated Annual Non-Bacteremic Pneumococcal Pneumonia Incidence by Age Group, 2013–2017

Conclusion

Reductions in NBPP among adults were primarily due to indirect effects of PCV13 use in children, with no additional declines following PCV13 introduction for adults aged ≥ 65 years.

Disclosures

Lee Harrison, MD, GSK (Consultant)Merck (Consultant)Pfizer (Consultant)Sanofi Pasteur (Consultant) Nisha B. Alden, MPH, CDC (Grant/Research Support)

180. Impact of Pneumococcal Conjugative Vaccine on Antibiotic Resistant Invasive Pneumococcal Disease in the United States

Background

Antibiotic-nonsusceptible invasive pneumococcal disease (NS-IPD) in the United States declined dramatically following the introduction of pneumococcal conjugative vaccines (7-valent, PCV7 in 2000, replaced by the 13-valent, PCV13 in 2010). We evaluated the long-term impact of PCV13 on NS-IPD.

Methods

IPD cases were identified through CDC’s Active Bacterial Core surveillance during 2005−2018. We applied 2012 Clinical and Laboratory Standards Institute breakpoints to minimum inhibitory concentrations determined by broth microdilution (2005−2014) or whole genome sequencing (2015−2018) and classified non-susceptible isolates as those intermediate or resistant to ≥1 antibiotic class. Isolates were serotyped and classified as PCV13 or non-vaccine type (NVT). Incidence rates (cases per 100,000) were calculated using United States Census Bureau population denominators.

Results

From 2005 to 2018, NS IPD incidence decreased from 8.5 to 3.2 among children < 5 years old and from 13.0 to 9.4 among adults ≥ 65 years old. Incidence of vaccine-type NS-IPD decreased in all age groups (Figure 1), while incidence of NVT NS-IPD increased in all age groups (Figure 2). The greatest absolute increase in NVT NS-IPD occurred among adults ≥ 65 years from 4.7 in 2005 to 7.2 in 2018. PCV13 serotypes contributed to 62% of NS-IPD (36% of NS-IPD caused by serotype 19A alone) in 2005−2009, and 27% of NS-IPD in 2014−18 (8% of NS-IPD caused by 19A). During 2014–18, NVTs 35B (11%), 33F (9%), 22F (9%), and 15A (9%) were the most common NS-IPD serotypes.

Figure 1. Incidence of vaccine type antibiotic non-susceptible invasive pneumococcal disease by age group, 2005−2018.

Figure 2. Incidence of non-vaccine type antibiotic non-susceptible invasive pneumococcal disease by age group, 2005−2018.

Conclusion

NS-IPD incidence decreased following PCV13 use in the United States, driven by reductions in PCV13 serotypes. Recent increases in NVT NS-IPD, most pronounced among older adults, have started to erode PCV impact on NS-IPD. PCVs in development that contain serotypes 22F and 33F could help to further reduce NS-IPD.

Disclosures

Lee Harrison, MD, GSK (Consultant)Merck (Consultant)Pfizer (Consultant)Sanofi Pasteur (Consultant)

1470. Epidemiology of Invasive Pneumococcal Disease (IPD) Following 18 years of Pneumococcal Conjugate Vaccine (PCV) Use in the United States

Background

PCVs have been recommended for U.S. children since 2000. A 7-valent vaccine (PCV7) was introduced in 2000. This was replaced by a 13-valent vaccine (PCV13) in 2010. PCV13 was also recommended for adults aged ≥ 65 years in August 2014. We evaluated PCV impact on IPD.

Methods

IPD cases (isolation of pneumococcus from sterile sites) were identified through CDC’s Active Bacterial Core surveillance during 1998-2018. Isolates were serotyped by Quellung or whole genome sequencing and classified as PCV13-type and non-vaccine-type (NVT). Incidence rates (cases/100,000) were calculated using U.S. Census Bureau population denominators.

Results

From 1998 through 2018, overall IPD rates among children aged < 5 years decreased by 93% (from 95 to 7 cases/100,000). PCV13-type IPD decreased by 98% (from 88 to 2 cases/100,000). Among adults aged ≥ 65 years, overall IPD rates decreased by 60% (from 61 to 25 cases/100,000). PCV13-type IPD rates declined 86% (from 46 to 7 cases/100,000). Declines were most dramatic in the years following PCV7 introduction, with additional declines after PCV13 introduction in children (Figures 1 and 2). Serotypes 3, 19A, and 19F caused most of the remaining PCV13-type IPD. NVT IPD rates did not change significantly among children. Among adults aged 50-64 years, NVT IPD increased by 83% (from 6 to 12 cases/100,000) (p< 0.01). Among adults aged ≥ 65 years, NVT IPD increased by 22% (from 15 to 18 cases/100,000) (p< 0.01). The most common NVTs in 2018 were 22F (10% of all IPD), 9N (7%) and 15A (5%). Among children, the proportion of cases with meningitis increased from 5% to 14% (p< 0.01), and the proportion with pneumonia/empyema increased from 17% to 31% (p< 0.01). Among adults, the proportion of cases with meningitis did not change (3%), while the proportion with pneumonia/empyema increased from 72% to 76% (p=0.01).

Figure 1: Incidence of invasive pneumococcal disease among children aged < 5 years, 1998-2018

Figure 2: Incidence of invasive pneumococcal disease among adults aged ≥ 65 years, 1998-2018

Conclusion

Overall IPD incidence among children and adults decreased following PCV introduction for children, driven primarily by reductions in PCV-type IPD. NVT IPD increased in older adults, but these increases did not eliminate reductions from PCV13-type IPD.

Disclosures

Lee Harrison, MD, GSK (Consultant)Merck (Consultant)Pfizer (Consultant)Sanofi Pasteur (Consultant)

Epidemiology of Invasive Early-Onset and Late-Onset Group B Streptococcal Disease in the United States, 2006 to 2015: Multistate Laboratory and Population-Based Surveillance

IMPORTANCE

Invasive disease owing to group B Streptococcus (GBS) remains an important cause of illness and death among infants younger than 90 days in the United States, despite declines in early-onset disease (EOD; with onset at 0-6 days of life) that are attributed to intrapartum antibiotic prophylaxis (IAP). Maternal vaccines to prevent infant GBS disease are currently under development.

OBJECTIVE

To describe incidence rates, case characteristics, antimicrobial resistance, and serotype distribution of EOD and late-onset disease (LOD; with onset at 7-89 days of life) in the United States from 2006 to 2015 to inform IAP guidelines and vaccine development.

DESIGN, SETTING, AND PARTICIPANTS

This study used active population-based and laboratory-based surveillance for invasive GBS disease conducted through Active Bacterial Core surveillance in selected counties of 10 states across the United States. Residents of Active Bacterial Core surveillance areas who were younger than 90 days and had invasive GBS disease in 2006 to 2015 were included. Data were analyzed from December 2017 to April 2018.

EXPOSURES

Group B Streptococcus isolated from a normally sterile site.

MAIN OUTCOMES AND MEASURES

Early-onset disease and LOD incidence rates and associated GBS serotypes and antimicrobial resistance.

RESULTS

The Active Bacterial Core surveillance program identified 1277 cases of EOD and 1387 cases of LOD. From 2006 to 2015, EOD incidence declined significantly from 0.37 to 0.23 per 1000 live births (P < .001), and LOD rates remained stable (mean, 0.31 per 1000 live births). Among the mothers of 1277 infants with EOD, 617 (48.3%) had no indications for IAP and did not receive it, and 278 (21.8%) failed to receive IAP despite having indications. Serotype data were available for 1743 of 1897 patients (91.3%) from 7 sites that collect GBS isolates. Among patients with EOD, serotypes Ia (242 [27.3%]) and III (242 [27.3%]) were most common. Among patients with LOD, serotype III was most common (481 [56.2%]), and this increased from 2006 to 2015 from 0.12 to 0.20 cases per 1000 live births (P < .001). Serotype IV caused 53 cases (6.2%) of EOD and LOD combined. The 6 most common serotypes (Ia, Ib, II, III, IV, and V) caused 881 EOD cases (99.3%) and 853 LOD cases (99.7%). No β-lactam resistance was identified; 359 isolates (20.8%) tested showed constitutive clindamycin resistance. In 2015, an estimated 840 EOD cases and 1265 LOD cases occurred nationally.

CONCLUSIONS AND RELEVANCE

The rates of LOD among US infants are now higher than EOD rates. Combined with addressing IAP implementation gaps, an effective vaccine covering the most common serotypes might further reduce EOD rates and help prevent LOD, for which there is no current public health intervention.