SARS-CoV-2 infection risk among vaccinated and unvaccinated household members during the Alpha variant surge - Denver, Colorado, and San Diego, California, January-April 2021.

BACKGROUND: COVID-19 vaccination reduces SARS-CoV-2 infection and transmission. However, evidence is emerging on the degree of protection across variants and in high-transmission settings. To better understand the protection afforded by vaccination specifically in a high-transmission setting, we examined household transmission of SARS-CoV-2 during a period of high community incidence with predominant SARS-CoV-2 B.1.1.7 (Alpha) variant, among vaccinated and unvaccinated contacts. METHODS: We conducted a household transmission investigation in San Diego County, California, and Denver, Colorado, during January-April 2021. Households were enrolled if they had at least one person with documented SARS-CoV-2 infection. We collected nasopharyngeal swabs, blood, demographic information, and vaccination history from all consenting household members. We compared infection risks (IRs), RT-PCR cycle threshold values, SARS-CoV-2 culture results, and antibody statuses among vaccinated and unvaccinated household contacts. RESULTS: We enrolled 493 individuals from 138 households. The SARS-CoV-2 variant was identified from 121/138 households (88%). The most common variants were Alpha (75/121, 62%) and Epsilon (19/121, 16%). There were no households with discordant lineages among household members. One fully vaccinated secondary case was symptomatic (13%); the other 5 were asymptomatic (87%). Among unvaccinated secondary cases, 105/108 (97%) were symptomatic. Among 127 households with a single primary case, the IR for household contacts was 45% (146/322; 95% Confidence Interval [CI] 40-51%). The observed IR was higher in unvaccinated (130/257, 49%, 95% CI 45-57%) than fully vaccinated contacts (6/26, 23%, 95% CI 11-42%). A lower proportion of households with a fully vaccinated primary case had secondary cases (1/5, 20%) than households with an unvaccinated primary case (66/108, 62%). CONCLUSIONS: Although SARS-CoV-2 infections in vaccinated household contacts were reported in this high transmission setting, full vaccination protected against SARS-CoV-2 infection. These findings further support the protective effect of COVID-19 vaccination and highlight the need for ongoing vaccination among eligible persons.

Comparison of Home Antigen Testing With RT-PCR and Viral Culture During the Course of SARS-CoV-2 Infection.

Importance: As self-collected home antigen tests become widely available, a better understanding of their performance during the course of SARS-CoV-2 infection is needed. Objective: To evaluate the diagnostic performance of home antigen tests compared with reverse transcription-polymerase chain reaction (RT-PCR) and viral culture by days from illness onset, as well as user acceptability. Design, Setting, and Participants: This prospective cohort study was conducted from January to May 2021 in San Diego County, California, and metropolitan Denver, Colorado. The convenience sample included adults and children with RT-PCR-confirmed infection who used self-collected home antigen tests for 15 days and underwent at least 1 nasopharyngeal swab for RT-PCR, viral culture, and sequencing. Exposures: SARS-CoV-2 infection. Main Outcomes and Measures: The primary outcome was the daily sensitivity of home antigen tests to detect RT-PCR-confirmed cases. Secondary outcomes included the daily percentage of antigen test, RT-PCR, and viral culture results that were positive, and antigen test sensitivity compared with same-day RT-PCR and cultures. Antigen test use errors and acceptability were assessed for a subset of participants. Results: This study enrolled 225 persons with RT-PCR-confirmed infection (median [range] age, 29 [1-83] years; 117 female participants [52%]; 10 [4%] Asian, 6 [3%] Black or African American, 50 [22%] Hispanic or Latino, 3 [1%] Native Hawaiian or Other Pacific Islander, 145 [64%] White, and 11 [5%] multiracial individuals) who completed 3044 antigen tests and 642 nasopharyngeal swabs. Antigen test sensitivity was 50% (95% CI, 45%-55%) during the infectious period, 64% (95% CI, 56%-70%) compared with same-day RT-PCR, and 84% (95% CI, 75%-90%) compared with same-day cultures. Antigen test sensitivity peaked 4 days after illness onset at 77% (95% CI, 69%-83%). Antigen test sensitivity improved with a second antigen test 1 to 2 days later, particularly early in the infection. Six days after illness onset, antigen test result positivity was 61% (95% CI, 53%-68%). Almost all (216 [96%]) surveyed individuals reported that they would be more likely to get tested for SARS-CoV-2 infection if home antigen tests were available over the counter. Conclusions and Relevance: The results of this cohort study of home antigen tests suggest that sensitivity for SARS-CoV-2 was moderate compared with RT-PCR and high compared with viral culture. The results also suggest that symptomatic individuals with an initial negative home antigen test result for SARS-CoV-2 infection should test again 1 to 2 days later because test sensitivity peaked several days after illness onset and improved with repeated testing.

Public Health Role of Academic Medical Center in Community Outbreak of Hepatitis A, San Diego County, California, USA, 2016-2018.

During 2016-2018, San Diego County, California, USA, experienced one of the largest hepatitis A outbreaks in the United States in 2 decades. In close partnership with local healthcare systems, San Diego County Public Health led a public health response to the outbreak that focused on a 3-pronged strategy to vaccinate, sanitize, and educate. Healthcare systems administered nearly half of the vaccinations delivered in San Diego County. At University of California San Diego Health, the use of informatics tools assisted with the identification of at-risk populations and with vaccine delivery across outpatient and inpatient settings. In addition, acute care facilities helped prevent further disease transmission by delaying the discharge of patients with hepatitis A who were experiencing homelessness. We assessed the public health roles that acute care hospitals can play during a large community outbreak and the critical nature of ongoing collaboration between hospitals and public health systems in controlling such outbreaks.

2019-nCoV: The Identify-Isolate-Inform (3I) Tool Applied to a Novel Emerging Coronavirus.

2019 Novel Coronavirus (2019-nCoV) is an emerging infectious disease closely related to MERS-CoV and SARS-CoV that was first reported in Wuhan City, Hubei Province, China in December 2019. As of January 2020, cases of 2019-nCoV are continuing to be reported in other Eastern Asian countries as well as in the United States, Europe, Australia, and numerous other countries. An unusually high volume of domestic and international travel corresponding to the beginning of the 2020 Chinese New Year complicated initial identification and containment of infected persons. Due to the rapidly rising number of cases and reported deaths, all countries should be considered at risk of imported 2019-nCoV. Therefore, it is essential for prehospital, clinic, and emergency department personnel to be able to rapidly assess 2019-nCoV risk and take immediate actions if indicated. The Identify-Isolate-Inform (3I) Tool, originally conceived for the initial detection and management of Ebola virus and later adjusted for other infectious agents, can be adapted for any emerging infectious disease. This paper reports a modification of the 3I Tool for use in the initial detection and management of patients under investigation for 2019-nCoV. After initial assessment for symptoms and epidemiological risk factors, including travel to affected areas and exposure to confirmed 2019-nCoV patients within 14 days, patients are classified in a risk-stratified system. Upon confirmation of a suspected 2019-nCoV case, affected persons must immediately be placed in airborne infection isolation and the appropriate public health agencies notified. This modified 3I Tool will assist emergency and primary care clinicians, as well as out-of-hospital providers, in effectively managing persons with suspected or confirmed 2019-nCoV.

Homelessness and Hepatitis A-San Diego County, 2016-2018.

BACKGROUND: Hepatitis A is a vaccine-preventable viral disease transmitted by the fecal-oral route. During 2016-2018, the County of San Diego investigated an outbreak of hepatitis A infections primarily among people experiencing homelessness (PEH) to identify risk factors and support control measures. At the time of the outbreak, homelessness was not recognized as an independent risk factor for the disease. METHODS: We tested the association between homelessness and infection with hepatitis A virus (HAV) using a test-negative study design comparing patients with laboratory-confirmed hepatitis A with control subjects who tested negative for HAV infection. We assessed risk factors for severe hepatitis A disease outcomes, including hospitalization and death, using multivariable logistic regression. We measured the frequency of indications for hepatitis A vaccination according to Advisory Committee on Immunization Practices (ACIP) guidelines. RESULTS: Among 589 outbreak-associated cases reported, 291 (49%) occurred among PEH. Compared with those who were not homeless, PEH had 3.3 (95% confidence interval [CI], 1.5-7.9) times higher odds of HAV infection, 2.5 (95% CI, 1.7-3.9) times higher odds of hospitalization, and 3.9 (95% CI, 1.1-16.9) times higher odds of death associated with hepatitis A. Among PEH, 212 (73%) patients recorded other ACIP indications for hepatitis A vaccination. CONCLUSIONS: PEH were at higher risk of infection with HAV and of severe hepatitis A disease outcomes compared with those not experiencing homelessness. Approximately one-fourth of PEH had no other ACIP indication for hepatitis A vaccination. These findings support the recent ACIP recommendation to add homelessness as an indication for hepatitis A vaccination.

Novel Treatment of a Vaccinia Virus Infection from an Occupational Needlestick - San Diego, California, 2019.

Vaccinia virus (VACV) is an orthopoxvirus used in smallpox vaccines, as a vector for novel cancer treatments, and for experimental vaccine research (1). The Advisory Committee on Immunization Practices (ACIP) recommends smallpox vaccination for laboratory workers who handle replication-competent VACV (1). For bioterrorism preparedness, the U.S. government stockpiles tecovirimat, the first Food and Drug Administration-approved antiviral for treatment of smallpox (caused by variola virus and globally eradicated in 1980*,†) (2). Tecovirimat has activity against other orthopoxviruses and can be administered under a CDC investigational new drug protocol. CDC was notified about an unvaccinated laboratory worker with a needlestick exposure to VACV, who developed a lesion on her left index finger. CDC and partners performed laboratory confirmation, contacted the study sponsor to identify the VACV strain, and provided oversight for the first case of laboratory-acquired VACV treated with tecovirimat plus intravenous vaccinia immunoglobulin (VIGIV). This investigation highlights 1) the misconception among laboratory workers about the virulence of VACV strains; 2) the importance of providing laboratorians with pathogen information and postexposure procedures; and 3) that although tecovirimat can be used to treat VACV infections, its therapeutic benefit remains unclear.

Pertussis: The Identify, Isolate, Inform Tool Applied to a Re-emerging Respiratory Illness.

Pertussis, commonly referred to as "whooping cough," is a highly contagious acute respiratory infection that has exhibited cyclical outbreaks throughout the last century. Although vaccines have provided some immunity, many populations, including infants and pregnant women, remain at risk for serious illness. Through the use of the novel "Identify, Isolate, Inform" (3I) tool, emergency department (ED) providers can readily recognize key symptoms of the disease and risk factors for exposure, thus curbing its transmission through early initiation of antimicrobial therapy and post-exposure prophylaxis. The three classic stages of pertussis include an initial catarrhal stage, characterized by nonspecific upper respiratory infection symptoms, which may advance to the paroxysmal stage, revealing the distinctive "whooping cough." This cough can persist for weeks to months leading into the convalescent stage. Household contacts of patients with suspected pertussis or other asymptomatic, high-risk populations (infants, pregnant women in their third trimester, and childcare workers) may benefit from post-exposure prophylactic therapy. The Pertussis 3I tool can also alert healthcare professionals to the proper respiratory droplet precautions during contact with a symptomatic patient, as well as isolation practices until antimicrobial treatment is in progress. ED personnel should then inform local public health departments of any suspected cases. All of these actions will ultimately aid public health in controlling the incidence of pertussis cases, thus ensuring the protection of the general public from this re-emerging respiratory illness.

Voluntarily Reported Immunization Registry Data: Reliability and Feasibility to Predict Immunization Rates, San Diego, California, 2013.

OBJECTIVES: Accurate data on immunization coverage levels are essential to public health program planning. Reliability of coverage estimates derived from immunization information systems (IISs) in states where immunization reporting by medical providers is not mandated by the state may be compromised by low rates of participation. To overcome this problem, data on coverage rates are often acquired through random-digit-dial telephone surveys, which require substantial time and resources. This project tested both the reliability of voluntarily reported IIS data and the feasibility of using these data to estimate regional immunization rates. METHODS: We matched telephone survey records for 553 patients aged 19-35 months obtained in 2013 to 430 records in the San Diego County IIS. We assessed concordance between survey data and IIS data using κ to measure the degree of nonrandom agreement. We used multivariable logistic regression models to investigate differences among demographic variables between the 2 data sets. These models were used to construct weights that enabled us to predict immunization rates in areas where reporting is not mandated. RESULTS: We found moderate agreement between the telephone survey and the IIS for the diphtheria, tetanus, and acellular pertussis (κ = 0.49), pneumococcal conjugate (κ = 0.49), and Haemophilus influenzae type b (κ = 0.46) vaccines; fair agreement for the varicella (κ = 0.39), polio (κ = 0.39), and measles, mumps, and rubella (κ = 0.35) vaccines; and slight agreement for the hepatitis B vaccine (κ = 0.17). CONCLUSIONS: Consistency in factors predicting immunization coverage levels in a telephone survey and IIS data confirmed the feasibility of using voluntarily reported IIS data to assess immunization rates in children aged 19-35 months.

Economic and Social Impact of Pertussis Among Adolescents in San Diego County.

PURPOSE: During recent pertussis epidemics, adolescents have experienced a large burden of disease. We assessed the impact of pertussis among San Diego adolescents and their households. METHODS: Parents of pertussis patients aged 13-17 years were surveyed about health care utilization, missed work and school, and other factors. Costs of medical visits, medication use, and lost wages were estimated. RESULTS: The parents of 53 (of 108 [49%]) eligible 2013 pertussis patients were interviewed; 51 (96%) of these patients previously received tetanus, diphtheria, and acellular pertussis vaccine. Medical visits included primary care (81%), urgent care (11%), and emergency department (9%); all patients received antibiotics. Forty-seven households (89%) received a post-exposure prophylaxis recommendation, and five (9%) reported ≥1 unpaid parental leave day. Thirty-eight patients (72%) missed ≥1 school day (mean = 5.4 days). Societal costs were estimated at $315.15 per household and $236,047.35 in San Diego during 2013-2014. CONCLUSIONS: Even among vaccinated adolescents, pertussis can result in considerable societal costs.

Notes from the field: fatal rat-bite fever in a child - San Diego County, California, 2013.

In August 2013, the County of San Diego Health and Human Services Agency was notified of a fatal case of rat-bite fever (RBF) in a previously healthy male, aged 10 years, who owned pet rats. Two days before his death, the patient experienced rigors, fevers, vomiting, headaches, and leg pains. His physician noted a fever of 102.6°F (39.2ºC), documented a normal examination, diagnosed viral gastroenteritis, and prescribed anti-nausea medication. During the next 24 hours, the patient experienced vomiting and persistent fever. He was confused and weak before collapsing at home. Paramedics reported the patient was unresponsive and had dilated pupils; resuscitation was initiated in the field and was continued for >1 hour after arrival at the emergency department but was unsuccessful. A complete blood count performed during resuscitation revealed anemia (hemoglobin 10.0 g/dL [normal = 13.5-18.0 g/dL], thrombocytopenia (platelets 40,000/µL [normal = 140,000-440,000/µL]), leukocytosis (white blood cells 17,900 cells/µL [normal = 4,000-10,500/µL]) with 16% band neutrophils; the patient also had evidence of disseminated intravascular coagulation. No rash or skin breakdown was noted. Lung, liver, and epiglottis tissue collected postmortem was positive for Streptobacillus moniliformis DNA by polymerase chain reaction.

Routine TBI screening following combat deployments.

A precise estimate of the rates of traumatic brain injury (TBI) in returning combat troops is difficult to establish given the challenges of screening large numbers of military personnel returning from combat deployments. The Brief Traumatic Brain Injury Screen (BTBIS) was implemented in the First Marine Expeditionary Force between 2004 and 2006. Nine percent of the 7909 marines who completed the BTBIS were considered having a positive screen; that is, they endorsed at least one injury mechanism and indicated a change in mental status at the time of injury. The majority of combat-related TBI's were due to multiple injury agents with the next largest group related to blast exposure only. Most importantly, of those who screened positive for TBI 70.5% (n=500) were first identified by the screen. Service members who endorsed items on the BTBIS were contacted for follow-up assessment of persistent symptoms related to TBI and clinical referrals were made as needed. Given the rate of positive TBI screens in this non-referred sample of military personnel returning from a combat deployment, routine TBI screening appears valuable in screening individuals who might not be identified otherwise. Furthermore, this study appears to refute the contention that routine TBI screening will result in an over-identification of TBI in this population.

To investigate the influence of acute vestibular impairment following mild traumatic brain injury on subsequent ability to remain on activity duty 12 months later.

The objective of this study was to investigate the relationship between acute vestibular dysfunction as measured by the Dizziness Handicap Inventory and the Dynamic Visual Acuity Test and the ability to remain on active duty status in the U.S. military 1 year after mild traumatic brain injury. This longitudinal prospective study was conducted by the Defense and Veterans Brain Injury Clinic at Marine Corp Base, Camp Pendleton, California. Participants (n = 47, controls = 44) were referrals to the clinic who had sustained a mild traumatic brain injury and were initially seen within 6 days of injury, then weekly for 1 month, and for follow-up 12 months later. The results demonstrated that those on active duty at 12 months were older in age, had more years of service, and had no history of psychiatric illness or apparent secondary gain issues. Acute vestibular dysfunction and demographic and injury variables were not significantly correlated or predictive of work status at 12 months.

Utility of Glasgow Coma Scale-Extended in symptom prediction following mild traumatic brain injury.

STUDY OBJECTIVE: To examine the efficacy of the Glasgow Coma Scale-Extended (GCS-E) for the prediction of symptoms commonly associated with mild traumatic brain injury (TBI). METHOD: Three hundred and sixty-one participants with a mild TBI were evaluated using the GCS-E and the Standardized Assessment of Concussion. A sub-group of 185 participants took part in a more extensive evaluation, which also included measures of depression and vestibular symptoms. All participants had a Glasgow Coma Scale score of 15, but experienced varying lengths of post-traumatic amnesia (PTA) as measured by the GCS-E. RESULTS: Use of the GCS-E for assessment of PTA duration revealed that longer lengths of amnesia following mild TBI were associated with greater incidence of dizziness, depression and cognitive impairments during the first weeks after injury. CONCLUSION: Results suggest that the GCS-E is a useful tool for the prediction of symptoms associated with mild TBI.