On September 12, 2023, CDC's Advisory Committee on Immunization Practices recommended updated 2023-2024 (updated) COVID-19 vaccination with a monovalent XBB.1.5-derived vaccine for all persons aged ≥6 months to prevent COVID-19, including severe disease. During fall 2023, XBB lineages co-circulated with JN.1, an Omicron BA.2.86 lineage that emerged in September 2023. These variants have amino acid substitutions that might increase escape from neutralizing antibodies. XBB lineages predominated through December 2023, when JN.1 became predominant in the United States. Reduction or failure of spike gene (S-gene) amplification (i.e., S-gene target failure [SGTF]) in real-time reverse transcription-polymerase chain reaction testing is a time-dependent, proxy indicator of JN.1 infection. Data from the Increasing Community Access to Testing SARS-CoV-2 pharmacy testing program were analyzed to estimate updated COVID-19 vaccine effectiveness (VE) (i.e., receipt versus no receipt of updated vaccination) against symptomatic SARS-CoV-2 infection, including by SGTF result. Among 9,222 total eligible tests, overall VE among adults aged ≥18 years was 54% (95% CI = 46%-60%) at a median of 52 days after vaccination. Among 2,199 tests performed at a laboratory with SGTF testing, VE 60-119 days after vaccination was 49% (95% CI = 19%-68%) among tests exhibiting SGTF and 60% (95% CI = 35%-75%) among tests without SGTF. Updated COVID-19 vaccines provide protection against symptomatic infection, including against currently circulating lineages. CDC will continue monitoring VE, including for expected waning and against severe disease. All persons aged ≥6 months should receive an updated COVID-19 vaccine dose.

The SARS-CoV-2 Omicron sublineage XBB was first detected in the United States in August 2022.* XBB together with a sublineage, XBB.1.5, accounted for >50% of sequenced lineages in the Northeast by December 31, 2022, and 52% of sequenced lineages nationwide as of January 21, 2023. COVID-19 vaccine effectiveness (VE) can vary by SARS-CoV-2 variant; reduced VE has been observed against some variants, although this is dependent on the health outcome of interest. The goal of the U.S. COVID-19 vaccination program is to prevent severe disease, including hospitalization and death (1); however, VE against symptomatic infection can provide useful insight into vaccine protection against emerging variants in advance of VE estimates against more severe disease. Data from the Increasing Community Access to Testing (ICATT) national pharmacy program for SARS-CoV-2 testing were analyzed to estimate VE of updated (bivalent) mRNA COVID-19 vaccines against symptomatic infection caused by BA.5-related and XBB/XBB.1.5-related sublineages among immunocompetent adults during December 1, 2022–January 13, 2023. Reduction or failure of spike gene (S-gene) amplification (SGTF) in real-time reverse transcription–polymerase chain reaction (RT-PCR) was used as a proxy indicator of infection with likely BA.5-related sublineages and S-gene target presence (SGTP) of infection with likely XBB/XBB.1.5-related sublineages (2). Among 29,175 nucleic acid amplification tests (NAATs) with SGTF or SGTP results available from adults who had previously received 2–4 monovalent COVID-19 vaccine doses, the relative VE of a bivalent booster dose given 2–3 months earlier compared with no bivalent booster in persons aged 18–49 years was 52% against symptomatic BA.5 infection and 48% against symptomatic XBB/XBB.1.5 infection. As new SARS-CoV-2 variants emerge, continued vaccine effectiveness monitoring is important. Bivalent vaccines appear to provide additional protection against symptomatic BA.5-related sublineage and XBB/XBB.1.5-related sublineage infections in persons who had previously received 2, 3, or 4 monovalent vaccine doses. All persons should stay up to date with recommended COVID-19 vaccines, including receiving a bivalent booster dose when they are eligible.

On June 18, 2022, the Advisory Committee on Immunization Practices (ACIP) issued interim recommendations for use of the 2-dose monovalent Moderna COVID-19 vaccine as a primary series for children aged 6 months-5 years* and the 3-dose monovalent Pfizer-BioNTech COVID-19 vaccine as a primary series for children aged 6 months-4 years,(†) based on safety, immunobridging, and limited efficacy data from clinical trials (1-3). Monovalent mRNA vaccine effectiveness (VE) against symptomatic SARS-CoV-2 infection was evaluated using the Increasing Community Access to Testing (ICATT) program, which provides SARS-CoV-2 testing to persons aged ≥3 years at pharmacy and community-based testing sites nationwide(§) (4,5). Among children aged 3-5 years with one or more COVID-19-like illness symptoms(¶) for whom a nucleic acid amplification test (NAAT) was performed during August 1, 2022-February 5, 2023, VE of 2 monovalent Moderna doses (complete primary series) against symptomatic infection was 60% (95% CI = 49% to 68%) 2 weeks-2 months after receipt of the second dose and 36% (95% CI = 15% to 52%) 3-4 months after receipt of the second dose. Among symptomatic children aged 3-4 years with NAATs performed during September 19, 2022-February 5, 2023, VE of 3 monovalent Pfizer-BioNTech doses (complete primary series) against symptomatic infection was 31% (95% CI = 7% to 49%) 2 weeks-4 months after receipt of the third dose; statistical power was not sufficient to estimate VE stratified by time since receipt of the third dose. Complete monovalent Moderna and Pfizer-BioNTech primary series vaccination provides protection for children aged 3-5 and 3-4 years, respectively, against symptomatic infection for at least the first 4 months after vaccination. CDC expanded recommendations for use of updated bivalent vaccines to children aged ≥6 months on December 9, 2022 (6), which might provide increased protection against currently circulating SARS-CoV-2 variants (7,8). Children should stay up to date with recommended COVID-19 vaccines, including completing the primary series; those who are eligible should receive a bivalent vaccine dose.

On September 1, 2022, bivalent COVID-19 mRNA vaccines, composed of components from the SARS-CoV-2 ancestral and Omicron BA.4/BA.5 strains, were recommended by the Advisory Committee on Immunization Practices (ACIP) to address reduced effectiveness of COVID-19 monovalent vaccines during SARS-CoV-2 Omicron variant predominance (1). Initial recommendations included persons aged ≥12 years (Pfizer-BioNTech) and ≥18 years (Moderna) who had completed at least a primary series of any Food and Drug Administration-authorized or -approved monovalent vaccine ≥2 months earlier (1). On October 12, 2022, the recommendation was expanded to include children aged 5-11 years. At the time of recommendation, immunogenicity data were available from clinical trials of bivalent vaccines composed of ancestral and Omicron BA.1 strains; however, no clinical efficacy data were available. In this study, effectiveness of the bivalent (Omicron BA.4/BA.5-containing) booster formulation against symptomatic SARS-CoV-2 infection was examined using data from the Increasing Community Access to Testing (ICATT) national SARS-CoV-2 testing program.* During September 14-November 11, 2022, a total of 360,626 nucleic acid amplification tests (NAATs) performed at 9,995 retail pharmacies for adults aged ≥18 years, who reported symptoms consistent with COVID-19 at the time of testing and no immunocompromising conditions, were included in the analysis. Relative vaccine effectiveness (rVE) of a bivalent booster dose compared with that of ≥2 monovalent vaccine doses among persons for whom 2-3 months and ≥8 months had elapsed since last monovalent dose was 30% and 56% among persons aged 18-49 years, 31% and 48% among persons aged 50-64 years, and 28% and 43% among persons aged ≥65 years, respectively. Bivalent mRNA booster doses provide additional protection against symptomatic SARS-CoV-2 in immunocompetent persons who previously received monovalent vaccine only, with relative benefits increasing with time since receipt of the most recent monovalent vaccine dose. Staying up to date with COVID-19 vaccination, including getting a bivalent booster dose when eligible, is critical to maximizing protection against COVID-19 (1).

PURPOSE: Information on incentives for COVID-19 testing is needed to understand effective practices that encourage testing uptake. We describe characteristics of those who received an incentive after performing a rapid antigen test. DESIGN: Cross-sectional descriptive analysis of survey data. SETTING: During April 29-May 9, 2021, COVID-19 rapid antigen testing was offered in 2 Maryland cities. SAMPLE: Convenience sample of 553 adults (≥18 years) who tested and received an incentive; 93% consented to survey. MEASURES: Survey questions assessed reasons for testing, testing history, barriers, and demographics. ANALYSIS: Robust Poisson regressions were used to determine characteristic differences based on testing history and between participants who would re-test in the future without an incentive vs participants who would not. RESULTS: The most common reasons for testing were the desire to be tested (n = 280; 54%) and convenience of location (n = 146; 28%). Those motivated by an incentive to test (n = 110; 21%) were 5.83 times as likely to state they would not test again without an incentive, compared to those with other reasons for testing (95% CI: 2.67-12.72, P < .001). CRITICAL LIMITATIONS: No comparative study group. CONCLUSION: Results indicate internal motivation and convenience were prominent factors supporting testing uptake. Incentives may increase community testing participation, particularly among people who have never tested. Keywords COVID-19, pandemic, incentives, health behavior, community testing.

Immediately following the March 13, 2020 declaration of COVID-19 as a national emergency (1), the U.S. government began implementing national testing programs for epidemiologic surveillance, monitoring of frontline workers and populations at higher risk for acquiring COVID-19, and identifying and allocating limited testing resources. Effective testing supports identification of COVID-19 cases; facilitates isolation, quarantine, and timely treatment measures that limit the spread of SARS-CoV-2 (the virus that causes COVID-19); and guides public health officials about the incidence of COVID-19 in a community. A White House Joint Task Force, co-led by the Department of Health and Human Services (HHS) and the Federal Emergency Management Agency (FEMA), created the Community-Based Testing Sites (CBTS) program working with state and local partners (2). This report describes the timeline, services delivered, and scope of the CBTS program. During March 19, 2020-April 11, 2021, the CBTS program conducted 11,661,923 SARS-CoV-2 tests at 8,319 locations across the United States and its territories, including 402,223 (3.5%) administered through Drive-Through Testing, 10,129,142 (86.9%) through Pharmacies+ Testing, and 1,130,558 (9.7%) through Surge Testing programs. Tests administered through the CBTS program yielded 1,176,959 (10.1%) positive results for SARS-CoV-2. Among tested persons with available race data,* positive test results were highest among American Indian or Alaska Native (14.1%) and Black persons (10.4%) and lowest among White persons (9.9%), Asian persons (7.3%), and Native Hawaiian or Other Pacific Islanders (6.4%). Among persons with reported ethnicity, 25.3% were Hispanic, 15.9% of whom received a positive test result. Overall, 82.0% of test results were returned within 2 days, but the percentage of test results returned within 2 days was as low as 40.7% in July 2020 and 59.3% in December 2020 during peak testing periods. Strong partnerships enabled a rapid coordinated response to establish the federally supported CBTS program to improve access to no-charge diagnostic testing, including for frontline workers, symptomatic persons and close contacts, and persons living in high-prevalence areas. In April 2021, the CBTS Pharmacies+ Testing and Surge Testing programs were expanded into the Increasing Community Access to Testing (ICATT) program. As of November 12, 2021, the CBTS and ICATT programs conducted approximately 26.6 million tests with approximately 10,000 active testing sites. Although the CBTS program represented a relatively small portion of overall U.S. SARS-CoV-2 testing, with its successful partnerships and adaptability, the CBTS program serves as a model to guide current community-based screening, surveillance, and disease control programs, and responses to future public health emergencies.

Yellow fever virus (YFV) live attenuated vaccine can, in rare cases, cause life-threatening disease, typically in patients with no previous history of severe viral illness. Autosomal recessive (AR) complete IFNAR1 deficiency was reported in one 12-yr-old patient. Here, we studied seven other previously healthy patients aged 13 to 80 yr with unexplained life-threatening YFV vaccine-associated disease. One 13-yr-old patient had AR complete IFNAR2 deficiency. Three other patients vaccinated at the ages of 47, 57, and 64 yr had high titers of circulating auto-Abs against at least 14 of the 17 individual type I IFNs. These antibodies were recently shown to underlie at least 10% of cases of life-threatening COVID-19 pneumonia. The auto-Abs were neutralizing in vitro, blocking the protective effect of IFN-α2 against YFV vaccine strains. AR IFNAR1 or IFNAR2 deficiency and neutralizing auto-Abs against type I IFNs thus accounted for more than half the cases of life-threatening YFV vaccine-associated disease studied here. Previously healthy subjects could be tested for both predispositions before anti-YFV vaccination.

Quality standards as part of an effective quality management system (QMS) are the cornerstone for generating high-quality test results. Next-generation sequencing (NGS) has the potential to improve both clinical diagnostics and public health surveillance efforts in multiple areas, including infectious diseases. However, the laboratories adopting NGS methods face significant challenges due to the complex and modular process design. This document summarizes the first phase of quality system guidance developed by the Centers for Disease Control and Prevention (CDC) NGS Quality Workgroup. The quality system essentials of personnel, equipment, and process management (quality control and validation) were prioritized based on a risk assessment using information gathered from participating CDC laboratories. Here, we present a prioritized QMS framework, including procedures and documentation tools, to assist laboratory implementation and maintenance of quality practices for NGS workflows.

BACKGROUND: Detections of influenza A subtype specific antibody responses are often complicated by the presence of cross-reactive antibodies. We developed two novel multiplex platforms for antibody detection. The multiplexed magnetic fluorescence microsphere immunoassay (MAGPIX) is a high throughput laboratory-based assay. Chembio Dual Path Platform (DPP) is a portable and rapid test that could be used in the field. METHODS: Twelve recombinant globular head domain hemagglutinin (GH HA1) antigens from A(H1N1)pdm09 (pH1N1), A(H2N2), A(H3N2), A(H5N1), A(H7N9), A(H9N2), A(H13N9), B/Victoria lineage, B/Yamagata lineage viruses, and protein A control were used. Human sera from U.S. residents either vaccinated (with H5N1 or pH1N1) or infected with pH1N1 influenza viruses, and sera from live bird market workers in Bangladesh (BDPW) were evaluated. GH HA1 antigens and serum adsorption using full ectodomain recombinant hemagglutinins from A(H1N1) and A(H3N2) were introduced into the platforms to reduce cross-reactivity. RESULTS: Serum adsorption reduced cross-reactivity to novel subtype HAs. Compared to traditional hemagglutination inhibition or microneutralization assays, when serum adsorption and the highest fold rise in signals were used to determine positivity, the correct subtype-specific responses were identified in 86% to 100% of U.S. residents exposed to influenza antigens through vaccination or infection (N=49). For detection of H5N1 specific antibodies in sera collected from BDPW, H5 sensitivity was 100% (6/6) for MAGPIX, 83% (5/6) for DPP; H5 specificity was 100% (15/15) and cross-reactivity against other subtype was 0% (0/6) for both platforms. CONCLUSION: MAGPIX and DPP platforms can be utilized for high-throughput and in-field detection of novel influenza virus infections.

Influenza hemagglutination inhibition (HI) and virus microneutralization assays (MN) are widely used for seroprevalence studies. However, these assays have limited field portability and are difficult to fully automate for high throughput laboratory testing. To address these issues, three multiplex influenza subtype-specific antibody detection assays were developed using recombinant hemagglutinin antigens in combination with Chembio, Luminex(R), and ForteBio(R) platforms. Assay sensitivity, specificity, and subtype cross-reactivity were evaluated using a panel of well characterized human sera. Compared to the traditional HI, assay sensitivity ranged from 87% to 92% and assay specificity in sera collected from unexposed persons ranged from 65% to 100% across the platforms. High assay specificity (86-100%) for A(H5N1) rHA was achieved for sera from exposed or unexposed to hetorosubtype influenza HAs. In contrast, assay specificity for A(H1N1)pdm09 rHA using sera collected from A/Vietnam/1204/2004 (H5N1) vaccinees in 2008 was low (22-30%) in all platforms. Although cross-reactivity against rHA subtype proteins was observed in each assay platform, the correct subtype specific responses were identified 78% to 94% of the time when paired samples were available for analysis. These results show that high throughput and portable multiplex assays that incorporate rHA can be used to identify influenza subtype specific infections.

Drawing evidence from epidemiology and exposure assessment studies and recommendations from expert practice, we describe a process to guide health care providers helping their patients who present with symptoms that might be associated with living in damp housing. We present the procedures in the form of a guided 2-part interview. The first part has 5 questions that triage the patient toward a more detailed questionnaire that reflects features of housing conditions known to be reliably associated with exposures to mold and dampness contaminants. We chose the questions based on the conditions associated with moisture problems in homes across the United States and Canada. The goal is to facilitate the clinician's effort to help patients reduce exposure to environmental triggers that elicit symptoms to better manage their disease.

Novel data streams (NDS), such as web search data or social media updates, hold promise for enhancing the capabilities of public health surveillance. In this paper, we outline a conceptual framework for integrating NDS into current public health surveillance. Our approach focuses on two key questions: What are the opportunities for using NDS and what are the minimal tests of validity and utility that must be applied when using NDS? Identifying these opportunities will necessitate the involvement of public health authorities and an appreciation of the diversity of objectives and scales across agencies at different levels (local, state, national, international). We present the case that clearly articulating surveillance objectives and systematically evaluating NDS and comparing the performance of NDS to existing surveillance data and alternative NDS data is critical and has not sufficiently been addressed in many applications of NDS currently in the literature.

The relative performance of ELISA using globular head domain (GH) and ectodomain hemagglutinins (HAs) as antigens to detect influenza A virus IgG antibody responses was assessed. Assay sensitivity and subtype cross-reactivity were evaluated using sera collected from recipients of monovalent H5N1 vaccine and A(H1N1)pdm09 virus-infected persons. Assay specificity was determined using collections of sera from either individuals unexposed to either H5N1 or A(H1N1)pdm09 viruses or exposed to H5N1 or A(H1N1)pdm09 viruses through vaccination or infection, respectively. ELISA using GH HA showed a similar degree of sensitivity, significantly higher specificity, and significantly lower subtype cross-reactivity compared to ELISA using ectodomain HA.

Dust mites are 8-legged arthropods that live in the house dust of homes located in regions where they are prevalent. They have been recognized as the major source of allergens in house dust since 1967. The most common species found in homes in temperate regions of the United States are Dermatophagoides farinae and Dermatophagoides pteronyssinus. In addition, others, such as Blomia tropicalis, can be found in homes in tropical and subtropical regions. | Dust mites feed on organic materials, including skin scales, fungi, yeasts, and bacteria. Because they are composed of approximately 75% water by weight, they maintain their water balance through uptake of water vapor when RH is at least approximately 65%. They are susceptible to water loss when humidity decreases below 65% and have decreased survival and reproduction with an RH below 50%. | Mites produce and excrete numerous allergens into the environment, including cysteine proteases such as Der p 1 and Der f 1, serine proteases including Der p 3, 6 and 9, and proteases that can activate protease-activated receptor-2, which are proinflammatory in humans through a non–IgE-dependent mechanism. Mites also produce glycosidases and carbohydrate-binding proteins and muscle, cytoskeleton, and calcium-binding proteins. There is cross-reactivity among various mite species and between mites and other related families, such as crustaceans and cockroaches.

A novel influenza A (H1N1) virus detected in April 2009 rapidly spread around the world. North American provincial and state laboratories have well-defined roles and responsibilities, including providing accurate, timely test results for patients and information for regional public health and other decision makers. We used the multidisciplinary response and rapid implementation of process changes based on Lean methods at the provincial public health laboratory in British Columbia, Canada, to improve laboratory surge capacity in the 2009 influenza pandemic. Observed and computer simulating evaluation results from rapid processes changes showed that use of Lean tools successfully expanded surge capacity, which enabled response to the 10-fold increase in testing demands.

Diagnostic tests for detecting emerging influenza virus strains with pandemic potential are critical for directing global influenza prevention and control activities. In 2008, the Centers for Disease Control and Prevention received US Food and Drug Administration approval for a highly sensitive influenza polymerase chain reaction (PCR) assay. Devices were deployed to public health laboratories in the United States and globally. Within 2 weeks of the first recognition of 2009 pandemic influenza H1N1, the Centers for Disease Control and Prevention developed and began distributing a new approved pandemic influenza H1N1 PCR assay, which used the previously deployed device platform to meet a >8-fold increase in specimen submissions. Rapid antigen tests were widely used by clinicians at the point of care; however, test sensitivity was low (40%-69%). Many clinical laboratories developed their own pandemic influenza H1N1 PCR assays to meet clinician demand. Future planning efforts should identify ways to improve availability of reliable testing to manage patient care and approaches for optimal use of molecular testing for detecting and controlling emerging influenza virus strains.

In this issue, Crawford et al. describe their experiences running a clinical diagnostic laboratory during the first 3 weeks of the influenza A pandemic (H1N1) 2009 outbreak (1). During the early weeks of the outbreak, their laboratory, which serves 15 hospitals and affiliated physician practices in the greater New York City metropolitan area, experienced an approximately 8x increase in respiratory virus testing, reaching a maximum of about 900 samples processed in 1 day.