Possible Exposures Among Mpox Patients Without Reported Male-to-Male Sexual Contact - Six U.S. Jurisdictions, November 1-December 14, 2022

The extent to which the 2022 mpox outbreak has affected persons without a recent history of male-to-male sexual contact (MMSC) is not well understood. During November 1-December 14, 2022, CDC partnered with six jurisdictional health departments to characterize possible exposures among mpox patients aged ≥18 years who did not report MMSC during the 3 weeks preceding symptom onset. Among 52 patients included in the analysis, 14 (27%) had a known exposure to a person with mpox, including sexual activity and other close intimate contact (eight) and household contact (six). Among 38 (73%) patients with no known exposure to a person with mpox, self-reported activities before illness onset included sexual activity and other close intimate contact (17; 45%), close face-to-face contact (14; 37%), attending large social gatherings (11; 29%), and being in occupational settings involving close skin-to-skin contact (10; 26%). These findings suggest that sexual activity remains an important route of mpox exposure among patients who do not report MMSC.

Mpox Cases Among Cisgender Women and Pregnant Persons - United States, May 11-November 7, 2022

Monkeypox (mpox) cases in the 2022 outbreak have primarily occurred among adult gay, bisexual, and other men who have sex with men (MSM); however, other populations have also been affected (1). To date, data on mpox in cisgender women and pregnant persons have been limited. Understanding transmission in these populations is critical for mpox prevention. In addition, among pregnant persons, Monkeypox virus can be transmitted to the fetus during pregnancy or to the neonate through close contact during or after birth (2-5). Adverse pregnancy outcomes, including spontaneous abortion and stillbirth, have been reported in previous mpox outbreaks (3). During May 11-November 7, 2022, CDC and U.S. jurisdictional health departments identified mpox in 769 cisgender women aged ≥15 years, representing 2.7% of all reported mpox cases.^† Among cases with available data, 44% occurred in cisgender women who were non-Hispanic Black or African American (Black), 25% who were non-Hispanic White (White), and 23% who were Hispanic or Latino (Hispanic). Among cisgender women with available data, 73% reported sexual activity or close intimate contact as the likely route of exposure, with mpox lesions most frequently reported on the legs, arms, and genitals. Twenty-three mpox cases were reported in persons who were pregnant or recently pregnant^§; all identified as cisgender women based on the mpox case report form.^¶ Four pregnant persons required hospitalization for mpox. Eleven pregnant persons received tecovirimat, and no adverse reactions were reported. Continued studies on mpox transmission risks in populations less commonly affected during the outbreak, including cisgender women and pregnant persons, are important to assess and understand the impact of mpox on sexual, reproductive, and overall health.

Epidemiologic and Clinical Features of Children and Adolescents Aged <18 Years with Monkeypox - United States, May 17-September 24, 2022

Data on monkeypox in children and adolescents aged <18 years are limited (1,2). During May 17–September 24, 2022, a total of 25,038 monkeypox cases were reported in the United States,^† primarily among adult gay, bisexual, and other men who have sex with men (3). During this period, CDC and U.S. jurisdictional health departments identified Monkeypox virus (MPXV) infections in 83 persons aged <18 years, accounting for 0.3% of reported cases. Among 28 children aged 0–12 years with monkeypox, 64% were boys, and most had direct skin-to-skin contact with an adult with monkeypox who was caring for the child in a household setting. Among 55 adolescents aged 13–17 years, most were male (89%), and male-to-male sexual contact was the most common presumed exposure route (66%). Most children and adolescents with monkeypox were non-Hispanic Black or African American (Black) (47%) or Hispanic or Latino (Hispanic) (35%). Most (89%) were not hospitalized, none received intensive care unit (ICU)–level care, and none died. Monkeypox in children and adolescents remains rare in the United States. Ensuring equitable access to monkeypox vaccination, testing, and treatment is a critical public health priority. Vaccination for adolescents with risk factors and provision of prevention information for persons with monkeypox caring for children might prevent additional infections.

872. Burden of Influenza Outbreaks in Long-Term Care Facilities in Philadelphia, 2012-2020

Background

In the United States, influenza and other acute respiratory viruses contribute to a high burden of disease in long-term care facility (LTCF) residents. We aim to characterize the disease patterns and inter-seasonal variation of influenza virus outbreaks in LTCFs and identify institutional, environmental, and public health interventions associated with differences in outbreak outcomes and characteristics.

Methods

We conducted a retrospective, longitudinal study of influenza outbreaks in LTCFs reported to the Philadelphia Department of Public Health (PDPH) over eight consecutive seasons (November 2012 through March 2020). Characteristics of individual outbreaks, facilities, and infection control measures were reported in the PDPH Influenza Outbreak database, while quality measures and other facility-level data were extracted from the CMS Nursing Home Compare (NHC) database. Cases of influenza-like illness (ILI) in residents and staff were reported.

Results

131 influenza outbreaks were reported among 56 facilities, leading to 1196 cases of ILI, 227 influenza-related hospitalizations and 20 deaths. The median number of facility residents affected per outbreak was 4 (range, 0-52), and the resident attack rate was 3.0% (IQR, 1.6-7.4). Facility staff were affected in 56 (43%) of outbreaks. A greater number of facility beds was associated with sites reporting 3 or more outbreaks compared to those that did not (180 vs 133 beds, p=0.019). Public health measures were associated with lower total attack rates for surveillance (1.9% vs 4.3%, p=0.0015), education (1.9% vs 5.1%, p=0.0004), visitation restrictions (1.8% vs 3.1%, p=0.049), and vaccination policies of staff and/or residents (1.6% vs 2.7%, p=0.047). Smaller outbreaks were associated with the implementation of droplet precautions (3 vs 6, p=0.0071), antiviral treatment and prophylaxis (3 vs 6, p=0.024), and admission restrictions (4 vs 7, p=0.015).

Conclusion

Larger facility size was associated with an increased frequency of outbreaks. Public health measures may reduce the size and severity of influenza outbreaks in LTCFs. These results emphasize the importance of ensuring consistent utilization of recommended infection prevention strategies.

Disclosures

All Authors: No reported disclosures

Varicella Outbreak Surveillance in Schools in Sentinel Jurisdictions, 2012-2015

BACKGROUND

In 2007, a routine second dose of varicella vaccine was recommended in the United States for children aged 4 to 6 years to better control varicella-zoster virus circulation and outbreaks. Sentinel varicella outbreak surveillance was established to assess feasibility of surveillance and describe outbreaks that are occurring.

METHODS

Through the Centers for Disease Control and Prevention Epidemiology Laboratory Capacity funding, health departments conducted active surveillance for varicella outbreaks in schools from 2012 to 2015. Outbreaks of varicella were defined as ≥5 cases in a school within at least 1 incubation period (21 days). School nurses, healthcare providers, or laboratories reported cases and outbreaks of varicella to health departments; demographic, vaccination, and clinical data were collected.

RESULTS

Georgia, Houston, Maine, Minnesota, New York City, and Philadelphia participated in all 3 years; Puerto Rico and West Virginia participated in 2012 to 2013; and Kansas and Arkansas participated in 2014 to 2015. Twenty-nine outbreaks including 262 cases were reported. The median size of the outbreaks was 7 cases (range, 5-31 cases), and the median duration was 31 days (range, 4-100 days). Of the case-patients associated with larger outbreaks (≥8 cases), 55.4% were unvaccinated, and 15.7% and 18.1% had received 1 or 2 doses of vaccine, respectively. In small outbreaks (5-7 cases), 33.3% of case-patients were unvaccinated, and 16.7% and 38.5% had received 1 or 2 doses of vaccine, respectively.

CONCLUSIONS

The majority of cases associated with outbreaks occurred in undervaccinated children (unvaccinated and 1-dose vaccine recipients). Outbreaks with a greater proportion of 2-dose vaccine recipients were smaller. Varicella outbreak surveillance is feasible, and continued monitoring of outbreaks remains important for describing the epidemiology of varicella during the 2-dose varicella vaccination program.

Varicella Vaccine Effectiveness in Preventing Community Transmission in the 2-Dose Era

OBJECTIVES

We examined overall and incremental effectiveness of 2-dose varicella vaccination in preventing community transmission of varicella among children aged 4 to 18 years in 2 active surveillance sites. One-dose varicella vaccine effectiveness (VE) was examined in those aged 1 to 18 years.

METHODS

From May 2009 through June 2011, varicella cases identified during active surveillance in Antelope Valley, CA and Philadelphia, PA were enrolled into a matched case-control study. Matched controls within 2 years of the patient's age were selected from immunization registries. A standardized questionnaire was administered to participants' parents, and varicella vaccination history was obtained from health care provider, immunization registry, or parent records. We used conditional logistic regression to estimate varicella VE against clinically diagnosed and laboratory-confirmed varicella.

RESULTS

A total of 125 clinically diagnosed varicella cases and 408 matched controls were enrolled. Twenty-nine cases were laboratory confirmed. One-dose VE (1-dose versus unvaccinated) was 75.6% (95% confidence interval [CI], 38.7%-90.3%) in preventing any clinically diagnosed varicella and 78.1% (95% CI, 12.7%-94.5%) against moderate or severe, clinically diagnosed disease (≥50 lesions). Among subjects aged ≥4 years, 2-dose VE (2-dose versus unvaccinated) was 93.6% (95% CI, 75.6%-98.3%) against any varicella and 97.9% (95% CI, 83.0%-99.7%) against moderate or severe varicella. Incremental effectiveness (2-dose versus 1-dose) was 87.5% against clinically diagnosed varicella and 97.3% against laboratory-confirmed varicella.

CONCLUSIONS

Two-dose varicella vaccination offered better protection against varicella from community transmission among school-aged children compared with 1-dose vaccination.

Comparing Active and Passive Varicella Surveillance in Philadelphia, 2005–2010: Recommendations for the Transition to Nationwide Passive Varicella Disease Surveillance

Objective.

The Philadelphia Department of Public Health (PDPH) conducts active surveillance for varicella in West Philadelphia. For its approximately 300 active surveillance sites, PDPH mandates biweekly reports of varicella (including zero cases) and performs intensive case investigations. Elsewhere in Philadelphia, surveillance sites passively report varicella cases, and abbreviated investigations are conducted. We used active varicella surveillance program data to inform the transition to nationwide passive varicella surveillance.

Methods.

We compared classification of reported cases, varicella disease incidence, and reporting completeness for active and passive surveillance areas for 2005–2010. We assessed reporting completeness using capture-recapture analysis of 2- to 18-year-old cases reported by schools/daycare centers and health-care providers.

Results.

From 2005 to 2010, PDPH received 3,280 passive and 969 active surveillance varicella case reports. Most passive surveillance reports were classified as probable cases (18% confirmed, 56% probable, and 26% excluded), whereas nearly all of the active surveillance reports were either confirmed or excluded (36% confirmed, 11% probable, and 53% excluded). Overall incidence rates calculated using confirmed/probable cases were similar in the active and passive surveillance areas. Detection of laboratory-confirmed, breakthrough, and moderate-to-severe cases was equivalent for both surveillance areas.

Conclusions.

Although active surveillance for varicella results in better classified cases, passive surveillance provides comparable data for monitoring disease trends in breakthrough and moderate-to-severe varicella. To further improve passive surveillance in the two-dose-varicella vaccine era, jurisdictions should consider conducting periodic enhanced surveillance, encouraging laboratory testing, and collecting additional varicella-specific variables for passive surveillance.

Impact of a routine two-dose varicella vaccination program on varicella epidemiology

OBJECTIVE

One-dose varicella vaccination for children was introduced in the United States in 1995. In 2006, a second dose was recommended to further decrease varicella disease and outbreaks. We describe the impact of the 2-dose vaccination program on varicella incidence, severity, and outbreaks in 2 varicella active surveillance areas.

METHODS

We examined varicella incidence rates and disease characteristics in Antelope Valley (AV), CA, and West Philadelphia, PA, and varicella outbreak characteristics in AV during 1995-2010.

RESULTS

In 2010, varicella incidence was 0.3 cases per 1000 population in AV and 0.1 cases per 1000 population in West Philadelphia: 76% and 67% declines, respectively, since 2006 and 98% declines in both sites since 1995; incidence declined in all age groups during 2006-2010. From 2006-2010, 61.7% of case patients in both surveillance areas had been vaccinated with 1 dose of varicella vaccine and 7.5% with 2 doses. Most vaccinated case patients had <50 lesions with no statistically significant differences among 1- and 2-dose cases (62.8% and 70.3%, respectively). Varicella-related hospitalizations during 2006-2010 declined >40% compared with 2002-2005 and >85% compared with 1995-1998. Twelve varicella outbreaks occurred in AV during 2007-2010, compared with 47 during 2003-2006 and 236 during 1995-1998 (P < .01).

CONCLUSIONS

Varicella incidence, hospitalizations, and outbreaks in 2 active surveillance areas declined substantially during the first 5 years of the 2-dose varicella vaccination program. Declines in incidence across all ages, including infants who are not eligible for varicella vaccination, and adults, in whom vaccination levels are low, provide evidence of the benefit of high levels of immunity in the population.

Validity of medical record documented varicella-zoster virus among unvaccinated cohorts

BACKGROUND

A varicella diagnosis or verification of disease history by any healthcare provider is currently accepted for determining evidence of immunity by the Advisory Committee on Immunization Practices (ACIP).

OBJECTIVE

To examine the accuracy of medical record (MR) documented varicella history as a measure of varicella-zoster virus (VZV) immunity among unvaccinated individuals born after 1980. We also assessed methods to practically implement ACIP guidelines to verify varicella history using medical records.

STUDY DESIGN

As part of a larger cross-sectional study conducted at three Philadelphia clinics from 2004-2006, we recruited 536 unvaccinated patients aged 5-19 y (birth years: 1985-2001). Varicella history was obtained from three sources: parent/patient interview, any MR documentation (sick and well visits) and MR documentation of a sick visit for varicella. All participants were tested for VZV IgG. For each source and three age groups (5-9, 10-14, 15-19 y old), positive predictive value (PPV) was calculated. Specificity of varicella history was compared between different sources using McNemar's Chi-square.

RESULTS

Among participants aged 5-9, 10-14 and 15-19 y the PPV for any MR documentation and sick visit diagnosis were 96% and 100%, 92% and 97%, and 99% and 100%, respectively. The specificity for sick visit documentation was higher than any MR documentation and patient/parent recall among all age groups; however, these differences were only statistically significant when comparing sick visit documentation to parent/patient recall for 10-14 y olds.

CONCLUSION

Sick visit documentation of varicella in the MR is an accurate predictor of varicella seropositivity and useful for confirming disease history among unvaccinated persons (birth years: 1985-2001). This method is a practical way to verify varicella history using the ACIP guidelines.

Knowledge, attitudes, and practices for diagnosing breakthrough varicella in the outpatient setting

OBJECTIVES

We assessed provider knowledge, attitudes, and practices for the management of breakthrough varicella and identified barriers to implementation of laboratory testing and reporting.

METHODS

We surveyed 145 health-care providers (HCPs) from 30 pediatric practices in Philadelphia who did not have a history of laboratory testing for breakthrough varicella. The self-administered survey instrument collected information on clinicians' practices for management of children presenting with rash, infection-control strategies, reporting to public health agencies, and laboratory testing.

RESULTS

Among the 144 HCPs who completed the survey, 73 (51%) had practiced for more than 10 years. While 115 HCPs (80%) would elect to evaluate a child with rash in the office, only 19 (13%) would submit diagnostics. When patients had a known recent exposure to varicella, 84 HCPs (58%) would use laboratory tests: 40% would use direct fluorescent antibody staining on a specimen from a cutaneous lesion, 24% would use polymerase chain reaction on a lesion specimen, 21% would use acute and convalescent serology, and 10% would use other tests. While waiting for test results, 82 HCPs (57%) would advise that the child be kept at home, 39 (27%) would notify the local health department, and 33 (23%) would inform the school nurse.

CONCLUSION

As varicella becomes increasingly uncommon, laboratory confirmation becomes more critical for appropriate diagnosis, similar to poliomyelitis and measles. Our findings suggest that HCPs need further education regarding laboratory confirmation, containment, and reporting of breakthrough varicella.

Validity of reported varicella history as a marker for varicella zoster virus immunity among unvaccinated children, adolescents, and young adults in the post-vaccine licensure era

OBJECTIVES

We assessed the validity of reported varicella history as a marker for varicella zoster virus immunity among unvaccinated persons 1 to 29 years of age, and we examined varicella disease characteristics associated with varicella zoster virus immunity among those reporting positive histories.

METHODS

We conducted a cross-sectional study at 7 community-based sites in Philadelphia, Pennsylvania, between June 2004 and May 2006 and recruited 1476 participants 1 to 29 years of age who had not been vaccinated against varicella. Sensitivity, specificity, and positive predictive value were determined by comparing self-reported or parent-reported varicella histories from a standardized study interview with varicella zoster virus immunoglobulin G serological results for each participant. We performed multivariate logistic regression analyses to determine which disease characteristics best predicted seropositivity.

RESULTS

The sensitivity of reported varicella history was highest (81%-89%) among participants > or =10 years of age, whereas specificity was highest among participants 1 to 4 years of age (99%) and > or =20 years (88%). Reported varicella history was highly predictive of seropositivity (>95%) only among participants > or =15 years of age. For participants 10 to 14 years of age, parental reports of a generalized itchy rash with 1 of the following were highly predictive of seropositivity: varicella transmission to another household member or being raised in a household with no other children. Among participants < or =9 years of age, no combination of disease characteristics was both highly predictive of seropositivity and common.

CONCLUSIONS

The validity of reported varicella history varies according to age, and a reported history is no longer highly predictive of seropositivity among cohorts born since 1994 (participants < or =9 years of age). Universal varicella vaccination, regardless of history, for these children should be considered, as should simplified criteria for varicella zoster virus immunity among unvaccinated persons born before 1994.

Varicella among adults: data from an active surveillance project, 1995-2005

We report detailed population-based data on varicella among adults. In 2 US varicella active surveillance sites with high vaccine coverage among young children, the incidence of varicella among adults declined 74% during 1995-2005. A low proportion (3%) of adults with varicella had been vaccinated, with no improvement over the decade of program implementation, suggesting that the decline was likely secondary to herd-immunity effects. Compared with children, adults had more severe varicella in terms of both clinical presentation and frequency of complications. However, <30% of adults with varicella were treated with acyclovir. Among adolescents, illness severity was intermediate between that in children and adults. Varicella cases are preventable through vaccination. As we enter the second decade of the varicella vaccination program in the United States, we need to ensure that susceptible adolescents and adults are adequately protected from varicella by vaccination and that those who acquire varicella are appropriately treated with effective antiviral treatment.

Varicella disease among vaccinated persons: clinical and epidemiological characteristics, 1997-2005

Approximately 1 in every 5 children who receives 1 dose of varicella vaccine may develop varicella disease, also known as breakthrough disease, if exposed to varicella-zoster virus. Currently, in communities with high vaccination coverage, varicella cases mostly occur in vaccinated individuals. We report on the first population-based description of the clinical and epidemiological characteristics of varicella in populations with increasing vaccine coverage between 1997 and 2005. In vaccinated children 1-14 years of age, varicella was most often mild and modified; the atypical disease presentation may result in diagnostic challenges to health care providers. However, despite the generally mild nature of these cases, approximately 25% caused >50 lesions, and some resulted in serious complications similar to those occurring in unvaccinated individuals. Continued surveillance of the risk and characteristics of breakthrough disease will be needed, to monitor the effect of the new 2-dose vaccine recommendation for children.

Changing varicella epidemiology in active surveillance sites--United States, 1995-2005

Significant reductions in varicella incidence were reported from 1995 to 2000 in the varicella active surveillance sites of Antelope Valley (AV), California, and West Philadelphia (WP), Pennsylvania. We examined incidence rates, median age, and vaccination status of case patients for 1995-2005. Coverage data were from the National Immunization Survey. By 2005, coverage among children 19-35 months of age reached 92% (AV) and 94% (WP); 57% and 64% of case patients in AV and WP, respectively, were vaccinated; and varicella incidence declined by 89.8% in AV and 90.4% in WP. Incidence declined in all age groups, especially among children <10 years of age in both sites and among adolescents 10-14 years of age in WP. In AV, since 2000, the incidence among adolescents 10-14 and 15-19 years of age increased. Implementation of school requirements through 10th grade in WP may explain the differences in the decline in incidence among adolescents. Continued surveillance will be important to monitor the impact that the 2-dose vaccine policy in children has on varicella epidemiology.

Validity of self-reported varicella disease history in pregnant women attending prenatal clinics

OBJECTIVE

The purpose of this study was to assess the validity of self-reported history for varicella disease relative to serological evidence of varicella immunity in pregnant women attending antenatal care at clinics located in two diverse geographical locations in the U.S. (Antelope Valley, California, and Philadelphia) with high varicella vaccination coverage.

METHODS

Pregnant women attending prenatal care appointments who needed blood drawn as part of their routine care were eligible to participate. Self-reported varicella disease history was obtained via questionnaire. Varicella serostatus was determined using a whole-cell enzyme-linked immunosorbent assay to test for varicella zoster virus-specific immunoglobulin G (VZV IgG) antibodies.

RESULTS

Of the 309 study participants from Antelope Valley and the 528 participants from Philadelphia who self-reported having had chickenpox disease, 308 (99.7%; 95% confidence interval [CI]: 98.2, 100) and 517 (97.9%; 95% CI: 96.3, 99.0), respectively, had serological evidence of immunity to varicella. Only 6.8% (95% CI: 3.9, 11.0) and 17.4% (95% CI: 13.1, 22.5) of women who self-reported having a negative or uncertain varicella disease history in Antelope Valley and Philadelphia, respectively, were seronegative for varicella antibodies.

CONCLUSION

Despite the dramatic changes in the epidemiology of varicella that have occurred since 1995 due to the introduction and subsequent widespread use of the varicella vaccine, self-reported history of varicella continues to be a strong predictor of VZV IgG antibodies in pregnant women. Negative or uncertain history remains poorly predictive of negative serostatus.