Influenza Vaccine Effectiveness Against Illness and Asymptomatic Infection in 2022-2023: A Prospective Cohort Study.

BACKGROUND: Previous estimates of vaccine effectiveness (VE) against asymptomatic influenza virus infection based on seroconversion have varied widely and may be biased. We estimated 2022-2023 influenza VE against illness and asymptomatic infection in a prospective cohort. METHODS: In the HEROES-RECOVER cohort, adults at increased occupational risk of influenza exposure across 7 US sites provided weekly symptom reports and nasal swabs for reverse transcription-polymerase chain reaction (RT-PCR) influenza testing. Laboratory-confirmed influenza virus infections were classified as symptomatic (≥1 symptom) or asymptomatic during the week of testing. Participants reported demographic information and vaccination through surveys; most sites verified vaccination through medical record and immunization registry review. Person-time was calculated as days from the site-specific influenza season start (September-October 2022) through date of infection, study withdrawal, or season end (May 2023). We compared influenza incidence among vaccinated versus unvaccinated participants overall, by symptom status, and by influenza A subtype, using Cox proportional hazards regression adjusted for site and occupation. We estimated VE as (1 - adjusted hazard ratio) × 100%. RESULTS: In total, 269 of 3785 (7.1%) participants had laboratory-confirmed influenza, including 263 (98%) influenza A virus infections and 201 (75%) symptomatic illnesses. Incidence of laboratory-confirmed influenza illness among vaccinated versus unvaccinated participants was 23.7 and 33.2 episodes per 100 000 person-days, respectively (VE: 38%; 95% CI: 15%-55%). Incidence of asymptomatic influenza virus infection was 8.0 versus 11.6 per 100 000 (VE: 13%; 95% CI: -47%, 49%). CONCLUSIONS: Vaccination reduced incidence of symptomatic but not asymptomatic influenza virus infection, suggesting that influenza vaccination attenuates progression from infection to illness.

Hybrid Immunity and SARS-CoV-2 Antibodies: Results of the HEROES-RECOVER Prospective Cohort Study.

BACKGROUND: There are limited data on whether hybrid immunity differs by count and order of immunity-conferring events (infection with severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2] or vaccination against coronavirus disease 2019 [COVID-19]). From a multi-site cohort of frontline workers, we examined the heterogeneity of the effect of hybrid immunity on SARS-CoV-2 antibody levels. METHODS: Exposures included event count and event order, categorized into 7 permutations. Outcome was level of serum antibodies against receptor-binding domain (RBD) of the ancestral SARS-CoV-2 spike protein (total RBD-binding immunoglobulin). Means were examined up to 365 days after each of the first to seventh events. RESULTS: Analysis included 5793 participants measured from 7 August 2020 to 15 April 2023. Hybrid immunity from infection before 1 or 2 vaccine doses elicited modestly superior antibody responses after the second and third events (compared with infections or vaccine doses alone). This superiority was not repeated after additional events. Among adults infected before vaccination, adjusted geometric mean ratios (95% confidence interval [CI]) of anti-RBD early response (versus vaccinated only) were 1.23 (1.14-1.33), 1.09 (1.03-1.14), 0.87 (.81-.94), and 0.99 (.85-1.15) after the second to fifth events, respectively. Post-vaccination infections elicited superior responses; adjusted geometric mean ratios (95% CI) of anti-RBD early response (versus vaccinated only) were 0.93 (.75-1.17), 1.11 (1.06-1.16), 1.17 (1.11-1.24), and 1.20 (1.07-1.34) after the second to fifth events, respectively. CONCLUSIONS: Evidence of heterogeneity in antibody levels by permutations of infection and vaccination history could inform COVID-19 vaccination policy.

Reduced Risk of SARS-CoV-2 Infection Among Household Contacts with Recent Vaccination and Past COVID-19 Infection: Results from Two Multi-Site Case-Ascertained Household Transmission Studies.

Households are a primary setting for transmission of SARS-CoV-2. We examined the role of prior SARS-CoV-2 immunity on the risk of infection in household close contacts. Households in the United States with an individual who tested positive for SARS-CoV-2 during September 2021-May 2023 were enrolled if the index case's illness began ≤6 days prior. Household members had daily self-collected nasal swabs tested by RT-PCR for SARS-CoV-2. The effects of prior SARS-CoV-2 immunity (vaccination, prior infection, or hybrid immunity) on SARS-CoV-2 infection risk among household contacts were assessed by robust, clustered multivariable Poisson regression. Of 1,532 contacts (905 households), 8% had immunity from prior infection alone, 51% from vaccination alone, 29% hybrid immunity, and 11% had no prior immunity. Sixty percent of contacts tested SARS-CoV-2-positive during follow-up. The adjusted risk of SARS-CoV-2 infection was lowest among contacts with vaccination and prior infection (aRR: 0.81, 95% CI: 0.70, 0.93, compared with contacts with no prior immunity) and was lowest when the last immunizing event occurred ≤6 months before COVID-19 affected the household (aRR: 0.69, 95% CI: 0.57, 0.83). In high-transmission settings like households, immunity from COVID-19 vaccination and prior infection was synergistic in protecting household contacts from SARS-CoV-2 infection.

Prevention and Attenuation of Covid-19 with the BNT162b2 and mRNA-1273 Vaccines.

BACKGROUND: Information is limited regarding the effectiveness of the two-dose messenger RNA (mRNA) vaccines BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna) in preventing infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and in attenuating coronavirus disease 2019 (Covid-19) when administered in real-world conditions. METHODS: We conducted a prospective cohort study involving 3975 health care personnel, first responders, and other essential and frontline workers. From December 14, 2020, to April 10, 2021, the participants completed weekly SARS-CoV-2 testing by providing mid-turbinate nasal swabs for qualitative and quantitative reverse-transcriptase-polymerase-chain-reaction (RT-PCR) analysis. The formula for calculating vaccine effectiveness was 100% × (1 - hazard ratio for SARS-CoV-2 infection in vaccinated vs. unvaccinated participants), with adjustments for the propensity to be vaccinated, study site, occupation, and local viral circulation. RESULTS: SARS-CoV-2 was detected in 204 participants (5%), of whom 5 were fully vaccinated (≥14 days after dose 2), 11 partially vaccinated (≥14 days after dose 1 and <14 days after dose 2), and 156 unvaccinated; the 32 participants with indeterminate vaccination status (<14 days after dose 1) were excluded. Adjusted vaccine effectiveness was 91% (95% confidence interval [CI], 76 to 97) with full vaccination and 81% (95% CI, 64 to 90) with partial vaccination. Among participants with SARS-CoV-2 infection, the mean viral RNA load was 40% lower (95% CI, 16 to 57) in partially or fully vaccinated participants than in unvaccinated participants. In addition, the risk of febrile symptoms was 58% lower (relative risk, 0.42; 95% CI, 0.18 to 0.98) and the duration of illness was shorter, with 2.3 fewer days spent sick in bed (95% CI, 0.8 to 3.7). CONCLUSIONS: Authorized mRNA vaccines were highly effective among working-age adults in preventing SARS-CoV-2 infection when administered in real-world conditions, and the vaccines attenuated the viral RNA load, risk of febrile symptoms, and duration of illness among those who had breakthrough infection despite vaccination. (Funded by the National Center for Immunization and Respiratory Diseases and the Centers for Disease Control and Prevention.).

SARS-CoV-2 Viral Shedding and Rapid Antigen Test Performance - Respiratory Virus Transmission Network, November 2022-May 2023.

As population immunity to SARS-CoV-2 evolves and new variants emerge, the role and accuracy of antigen tests remain active questions. To describe recent test performance, the detection of SARS-CoV-2 by antigen testing was compared with that by reverse transcription-polymerase chain reaction (RT-PCR) and viral culture testing during November 2022-May 2023. Participants who were enrolled in a household transmission study completed daily symptom diaries and collected two nasal swabs (tested for SARS-CoV-2 via RT-PCR, culture, and antigen tests) each day for 10 days after enrollment. Among participants with SARS-CoV-2 infection, the percentages of positive antigen, RT-PCR, and culture results were calculated each day from the onset of symptoms or, in asymptomatic persons, from the date of the first positive test result. Antigen test sensitivity was calculated using RT-PCR and viral culture as references. The peak percentage of positive antigen (59.0%) and RT-PCR (83.0%) results occurred 3 days after onset, and the peak percentage of positive culture results (52%) occurred 2 days after onset. The sensitivity of antigen tests was 47% (95% CI = 44%-50%) and 80% (95% CI = 76%-85%) using RT-PCR and culture, respectively, as references. Clinicians should be aware of the lower sensitivity of antigen testing compared with RT-PCR, which might lead to false-negative results. This finding has implications for timely initiation of SARS-CoV-2 antiviral treatment, when early diagnosis is essential; clinicians should consider RT-PCR for persons for whom antiviral treatment is recommended. Persons in the community who are at high risk for severe COVID-19 illness and eligible for antiviral treatment should seek testing from health care providers with the goal of obtaining a more sensitive diagnostic test than antigen tests (i.e., an RT-PCR test).

Cutting Edge: T Cell Responses to B.1.1.529 (Omicron) SARS-CoV-2 Variant Induced by COVID-19 Infection and/or mRNA Vaccination Are Largely Preserved.

Several studies have demonstrated that the SARS-CoV-2 variant-of-concern B.1.1.529 (Omicron) exhibits a high degree of escape from Ab neutralization. Therefore, it is critical to determine how well the second line of adaptive immunity, T cell memory, performs against Omicron. To this purpose, we analyzed a human cohort (n = 327 subjects) of two- or three-dose mRNA vaccine recipients and COVID-19 postinfection subjects. We report that T cell responses against Omicron were largely preserved. IFN-γ-producing T cell responses remained equivalent to the response against the ancestral strain (WA1/2020), with some (∼20%) loss in IL-2 single or IL-2+IFN-γ+ polyfunctional responses. Three-dose vaccinated participants had similar responses to Omicron relative to post-COVID-19 participants and exhibited responses significantly higher than those receiving two mRNA vaccine doses. These results provide further evidence that a three-dose vaccine regimen benefits the induction of optimal functional T cell immune memory.

Effectiveness of Bivalent mRNA COVID-19 Vaccines in Preventing SARS-CoV-2 Infection in Children and Adolescents Aged 5 to 17 Years.

Importance: Bivalent mRNA COVID-19 vaccines were recommended in the US for children and adolescents aged 12 years or older on September 1, 2022, and for children aged 5 to 11 years on October 12, 2022; however, data demonstrating the effectiveness of bivalent COVID-19 vaccines are limited. Objective: To assess the effectiveness of bivalent COVID-19 vaccines against SARS-CoV-2 infection and symptomatic COVID-19 among children and adolescents. Design, Setting, and Participants: Data for the period September 4, 2022, to January 31, 2023, were combined from 3 prospective US cohort studies (6 sites total) and used to estimate COVID-19 vaccine effectiveness among children and adolescents aged 5 to 17 years. A total of 2959 participants completed periodic surveys (demographics, household characteristics, chronic medical conditions, and COVID-19 symptoms) and submitted weekly self-collected nasal swabs (irrespective of symptoms); participants submitted additional nasal swabs at the onset of any symptoms. Exposure: Vaccination status was captured from the periodic surveys and supplemented with data from state immunization information systems and electronic medical records. Main Outcome and Measures: Respiratory swabs were tested for the presence of the SARS-CoV-2 virus using reverse transcriptase-polymerase chain reaction. SARS-CoV-2 infection was defined as a positive test regardless of symptoms. Symptomatic COVID-19 was defined as a positive test and 2 or more COVID-19 symptoms within 7 days of specimen collection. Cox proportional hazards models were used to estimate hazard ratios for SARS-CoV-2 infection and symptomatic COVID-19 among participants who received a bivalent COVID-19 vaccine dose vs participants who received no vaccine or monovalent vaccine doses only. Models were adjusted for age, sex, race, ethnicity, underlying health conditions, prior SARS-CoV-2 infection status, geographic site, proportion of circulating variants by site, and local virus prevalence. Results: Of the 2959 participants (47.8% were female; median age, 10.6 years [IQR, 8.0-13.2 years]; 64.6% were non-Hispanic White) included in this analysis, 25.4% received a bivalent COVID-19 vaccine dose. During the study period, 426 participants (14.4%) had laboratory-confirmed SARS-CoV-2 infection. Among these 426 participants, 184 (43.2%) had symptomatic COVID-19, 383 (89.9%) were not vaccinated or had received only monovalent COVID-19 vaccine doses (1.38 SARS-CoV-2 infections per 1000 person-days), and 43 (10.1%) had received a bivalent COVID-19 vaccine dose (0.84 SARS-CoV-2 infections per 1000 person-days). Bivalent vaccine effectiveness against SARS-CoV-2 infection was 54.0% (95% CI, 36.6%-69.1%) and vaccine effectiveness against symptomatic COVID-19 was 49.4% (95% CI, 22.2%-70.7%). The median observation time after vaccination was 276 days (IQR, 142-350 days) for participants who received only monovalent COVID-19 vaccine doses vs 50 days (IQR, 27-74 days) for those who received a bivalent COVID-19 vaccine dose. Conclusion and Relevance: The bivalent COVID-19 vaccines protected children and adolescents against SARS-CoV-2 infection and symptomatic COVID-19. These data demonstrate the benefit of COVID-19 vaccine in children and adolescents. All eligible children and adolescents should remain up to date with recommended COVID-19 vaccinations.

Symptoms, viral loads, and rebound among COVID-19 outpatients treated with nirmatrelvir/ritonavir compared to propensity score matched untreated individuals.

BACKGROUND: Nirmatrelvir/ritonavir (N/R) reduces severe outcomes among patients with COVID-19; however, rebound after treatment has been reported. We compared symptom and viral dynamics in community-based individuals with COVID-19 who completed N/R and similar untreated individuals. METHODS: We identified symptomatic participants who tested SARS-CoV-2 positive and were N/R eligible from a COVID-19 household transmission study: index cases from ambulatory settings and their households were enrolled, collecting daily symptoms, medication use, and respiratory specimens for quantitative PCR for 10 days, March 2022-May 2023. Participants who completed N/R (treated) were propensity score matched to untreated participants. We compared symptom rebound, viral load (VL) rebound, average daily symptoms, and average daily VL by treatment status measured after N/R completion or, if untreated, seven days after symptom onset. RESULTS: Treated (n=130) and untreated participants (n=241) had similar baseline characteristics. After treatment completion, treated participants had greater occurrence of symptom rebound (32% vs 20%; p=0.009) and VL rebound (27% vs 7%; p<0.001). Average daily symptoms were lower among treated participants compared to untreated participants without symptom rebound (1.0 vs 1.6; p<0.01), but not statistically lower with symptom rebound (3.0 vs 3.4; p=0.5). Treated participants had lower average daily VLs without VL rebound (0.9 vs 2.6; p<0.01), but not statistically lower with VL rebound (4.8 vs 5.1; p=0.7). CONCLUSIONS: Individuals who completed N/R experienced fewer symptoms and lower VL but were more likely to have rebound compared to untreated individuals. Providers should still prescribe N/R, when indicated, and communicate possible increased rebound risk to patients.

Severe Acute Respiratory Syndrome Coronavirus 2 Infection History and Antibody Response to 3 Coronavirus Disease 2019 Messenger RNA Vaccine Doses.

BACKGROUND: Data on antibody kinetics are limited among individuals previously infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). From a cohort of healthcare personnel and other frontline workers in 6 US states, we assessed antibody waning after messenger RNA (mRNA) dose 2 and response to dose 3 according to SARS-CoV-2 infection history. METHODS: Participants submitted sera every 3 months, after SARS-CoV-2 infection, and after each mRNA vaccine dose. Sera were tested for antibodies and reported as area under the serial dilution curve (AUC). Changes in AUC values over time were compared using a linear mixed model. RESULTS: Analysis included 388 participants who received dose 3 by November 2021. There were 3 comparison groups: vaccine only with no known prior SARS-CoV-2 infection (n = 224); infection prior to dose 1 (n = 123); and infection after dose 2 and before dose 3 (n = 41). The interval from dose 2 and dose 3 was approximately 8 months. After dose 3, antibody levels rose 2.5-fold (95% confidence interval [CI] = 2.2-3.0) in group 2 and 2.9-fold (95% CI = 2.6-3.3) in group 1. Those infected within 90 days before dose 3 (and median 233 days [interquartile range, 213-246] after dose 2) did not increase significantly after dose 3. CONCLUSIONS: A third dose of mRNA vaccine typically elicited a robust humoral immune response among those with primary vaccination regardless of SARS-CoV-2 infection >3 months prior to boosting. Those with infection <3 months prior to boosting did not have a significant increase in antibody concentrations in response to a booster.

Risk Factors for Reinfection with SARS-CoV-2 Omicron Variant among Previously Infected Frontline Workers.

In a cohort of essential workers in the United States previously infected with SARS-CoV-2, risk factors for reinfection included being unvaccinated, infrequent mask use, time since first infection, and being non-Hispanic Black. Protecting workers from reinfection requires a multipronged approach including up-to-date vaccination, mask use as recommended, and reduction in underlying health disparities.

Serum per- and polyfluoroalkyl substance concentrations and longitudinal change in post-infection and post-vaccination SARS-CoV-2 antibodies.

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous throughout the United States. Previous studies have shown PFAS exposure to be associated with a reduced immune response. However, the relationship between serum PFAS and antibody levels following SARS-CoV-2 infection or COVID-19 vaccination has not been examined. We examined differences in peak immune response and the longitudinal decline of antibodies following SARS-CoV-2 infection and COVID-19 vaccination by serum PFAS levels in a cohort of essential workers in the United States. We measured serum antibodies using an in-house semi-quantitative enzyme-linked immunosorbent assay (ELISA). Two cohorts contributed blood samples following SARS-CoV-2 infection or COVID-19 vaccination. We used linear mixed regression models, adjusting for age, race/ethnicity, gender, presence of chronic conditions, location, and occupation, to estimate differences in immune response with respect to serum PFAS levels. Our study populations included 153 unvaccinated participants that contributed 316 blood draws over a 14-month period following infection, and 860 participants and 2451 blood draws over a 12-month period following vaccination. Higher perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA) concentrations were associated with a lower peak antibody response after infection (p = 0.009, 0.031, 0.015). Higher PFOS, perfluorooctanoic acid (PFOA), PFHxS, and PFNA concentrations were associated with slower declines in antibodies over time after infection (p = 0.003, 0.014, 0.026, 0.025). PFOA, PFOS, PFHxS, and PFNA serum concentrations prior to vaccination were not associated with differences in peak antibody response after vaccination or with differences in decline of antibodies over time after vaccination. These results suggest that elevated PFAS may impede potential immune response to SARS-CoV-2 infection by blunting peak antibody levels following infection; the same finding was not observed for immune response to vaccination.

Disease and social factors associated with healthcare utilization for the treatment of SARS-CoV-2 infections in a longitudinal cohort of essential workers in Arizona.

BACKGROUND: Demands on health systems due to COVID-19 are substantial, but drivers of healthcare utilization are not well defined in non-severe SARS-CoV-2 infections. Among a prospective cohort of frontline workers from July 2020 to February 2023, we assessed predictors of healthcare utilization during SARS-CoV-2 infection. METHODS: Weekly specimens tested via real-time reverse transcriptase polymerase chain reaction analysis. Participants reported sociodemographic, health status information, and illness experience information. Primary outcome was healthcare utilization during SARS-CoV-2 infection. Predictors included sociodemographic characteristics, baseline health status, and measures of illness severity. Multivariable logistic regression was utilized to generate odds ratios for predictors of healthcare utilization. RESULTS: 1,923 SARS-CoV-2 infections (1,276 first infections and 647 reinfections from 4,208 participants): 1221 (63.5%) individuals were between 40 and 65 years old; 1115 (58.0%) were female; 449 (23.3%) were Hispanic and 1305 (67.9%) non-Hispanic White. 294 (15.3%) individuals sought medical care during first infection, 106 (5.5%) during reinfection. Sociodemographic and baseline health characteristics were not associated with healthcare utilization during infections from any variant for first infections, while age (OR 1.04, 95%CI 1.01-1.07) was during Omicron reinfection. In first infection, number of symptoms (OR 1.16, 95%CI 1.00-1.36 in Origin/Alpha, OR 1.12, 95%CI 1.00-1.49 in Delta, OR 1.09, 95%CI 1.01-1.16 in Omicron), number of days spent in bed (OR 1.13, 95%CI 1.02-1.33 in Origin/Alpha, OR 1.23, 95%CI 1.00-1.59 in Delta, OR 1.12, 95%CI 1.03-1.22 in Omicron), and illness duration (OR 1.01, 95%CI 1.00-1.04 in Origin/Alpha, OR 1.01, 95%CI 1.00-1.03 in Delta, OR 1.01, 95%CI 1.00-1.02 in Omicron) were related to healthcare utilization for all variants. Number of days in bed (OR 1.12, 95%CI 1.01-1.27), illness duration (OR 1.01, 95%CI 1.00-1.02), and hours of work missed (OR 2.24, 95%CI 1.11-4.74) were positively associated with healthcare utilization during Omicron reinfection. CONCLUSION: The main factors associated with healthcare utilization for SARS-CoV-2 infection were symptom severity and duration. Practices and therapeutics aimed at decreasing these factors would be most helpful in easing the burden on health systems.

Household Transmission of Influenza A Viruses in 2021-2022.

Importance: Influenza virus infections declined globally during the COVID-19 pandemic. Loss of natural immunity from lower rates of influenza infection and documented antigenic changes in circulating viruses may have resulted in increased susceptibility to influenza virus infection during the 2021-2022 influenza season. Objective: To compare the risk of influenza virus infection among household contacts of patients with influenza during the 2021-2022 influenza season with risk of influenza virus infection among household contacts during influenza seasons before the COVID-19 pandemic in the US. Design, Setting, and Participants: This prospective study of influenza transmission enrolled households in 2 states before the COVID-19 pandemic (2017-2020) and in 4 US states during the 2021-2022 influenza season. Primary cases were individuals with the earliest laboratory-confirmed influenza A(H3N2) virus infection in a household. Household contacts were people living with the primary cases who self-collected nasal swabs daily for influenza molecular testing and completed symptom diaries daily for 5 to 10 days after enrollment. Exposures: Household contacts living with a primary case. Main Outcomes and Measures: Relative risk of laboratory-confirmed influenza A(H3N2) virus infection in household contacts during the 2021-2022 season compared with prepandemic seasons. Risk estimates were adjusted for age, vaccination status, frequency of interaction with the primary case, and household density. Subgroup analyses by age, vaccination status, and frequency of interaction with the primary case were also conducted. Results: During the prepandemic seasons, 152 primary cases (median age, 13 years; 3.9% Black; 52.0% female) and 353 household contacts (median age, 33 years; 2.8% Black; 54.1% female) were included and during the 2021-2022 influenza season, 84 primary cases (median age, 10 years; 13.1% Black; 52.4% female) and 186 household contacts (median age, 28.5 years; 14.0% Black; 63.4% female) were included in the analysis. During the prepandemic influenza seasons, 20.1% (71/353) of household contacts were infected with influenza A(H3N2) viruses compared with 50.0% (93/186) of household contacts in 2021-2022. The adjusted relative risk of A(H3N2) virus infection in 2021-2022 was 2.31 (95% CI, 1.86-2.86) compared with prepandemic seasons. Conclusions and Relevance: Among cohorts in 5 US states, there was a significantly increased risk of household transmission of influenza A(H3N2) in 2021-2022 compared with prepandemic seasons. Additional research is needed to understand reasons for this association.

Implementing Psychological First Aid for Healthcare Workers During the COVID-19 Pandemic: A Feasibility Study of the ICARE Model.

Maintaining the resilience of healthcare workers (HCWs) during the protracted COVID-19 pandemic is critical as chronic stress is associated with burnout, inability to provide high-quality care, and decreased attentiveness to infection prevention protocols. Between May and July 2020, we implemented the ICARE model of psychological first aid (PFA) in a novel online (i.e., telehealth) format to address the psychological support needs of HCWs during the COVID-19 pandemic. We found that HCWs needed psychological support related to obtaining clear information about pandemic policies and guidelines, navigating new rules and responsibilities, and processing overwhelming and conflicting emotions. The HCWs in our program repeatedly expressed appreciation for the support we provided. Future directions include establishing online discussion forums, increasing opportunities for individual support, and training HCWs to provide peer support using PFA. This program has far-reaching potential benefit to HCWs and to society at large in the context of a pandemic.

Cross-Sectional Study of Clinical Predictors of Coccidioidomycosis, Arizona, USA.

Demographic and clinical indicators have been described to support identification of coccidioidomycosis; however, the interplay of these conditions has not been explored in a clinical setting. In 2019, we enrolled 392 participants in a cross-sectional study for suspected coccidioidomycosis in emergency departments and inpatient units in Coccidioides-endemic regions. We aimed to develop a predictive model among participants with suspected coccidioidomycosis. We applied a least absolute shrinkage and selection operator to specific coccidioidomycosis predictors and developed univariable and multivariable logistic regression models. Univariable models identified elevated eosinophil count as a statistically significant predictive feature of coccidioidomycosis in both inpatient and outpatient settings. Our multivariable outpatient model also identified rash (adjusted odds ratio 9.74 [95% CI 1.03-92.24]; p = 0.047) as a predictor. Our results suggest preliminary support for developing a coccidioidomycosis prediction model for use in clinical settings.

Effectiveness of 2-Dose BNT162b2 (Pfizer BioNTech) mRNA Vaccine in Preventing SARS-CoV-2 Infection Among Children Aged 5-11 Years and Adolescents Aged 12-15 Years - PROTECT Cohort, July 2021-February 2022.

The BNT162b2 (Pfizer-BioNTech) mRNA COVID-19 vaccine was recommended by CDC's Advisory Committee on Immunization Practices for persons aged 12-15 years (referred to as adolescents in this report) on May 12, 2021, and for children aged 5-11 years on November 2, 2021 (1-4). Real-world data on vaccine effectiveness (VE) in these age groups are needed, especially because when the B.1.1.529 (Omicron) variant became predominant in the United States in December 2021, early investigations of VE demonstrated a decline in protection against symptomatic infection for adolescents aged 12-15 years and adults* (5). The PROTECT† prospective cohort of 1,364 children and adolescents aged 5-15 years was tested weekly for SARS-CoV-2, irrespective of symptoms, and upon COVID-19-associated illness during July 25, 2021-February 12, 2022. Among unvaccinated participants (i.e., those who had received no COVID-19 vaccine doses) with any laboratory-confirmed SARS-CoV-2 infection, those with B.1.617.2 (Delta) variant infections were more likely to report COVID-19 symptoms (66%) than were those with Omicron infections (49%). Among fully vaccinated children aged 5-11 years, VE against any symptomatic and asymptomatic Omicron infection 14-82 days (the longest interval after dose 2 in this age group) after receipt of dose 2 of the Pfizer-BioNTech vaccine was 31% (95% CI = 9%-48%), adjusted for sociodemographic characteristics, health information, frequency of social contact, mask use, location, and local virus circulation. Among adolescents aged 12-15 years, adjusted VE 14-149 days after dose 2 was 87% (95% CI = 49%-97%) against symptomatic and asymptomatic Delta infection and 59% (95% CI = 22%-79%) against Omicron infection. Fully vaccinated participants with Omicron infection spent an average of one half day less sick in bed than did unvaccinated participants with Omicron infection. All eligible children and adolescents should remain up to date with recommended COVID-19 vaccinations.

Association of mRNA Vaccination With Clinical and Virologic Features of COVID-19 Among US Essential and Frontline Workers.

Importance: Data on the epidemiology of mild to moderately severe COVID-19 are needed to inform public health guidance. Objective: To evaluate associations between 2 or 3 doses of mRNA COVID-19 vaccine and attenuation of symptoms and viral RNA load across SARS-CoV-2 viral lineages. Design, Setting, and Participants: A prospective cohort study of essential and frontline workers in Arizona, Florida, Minnesota, Oregon, Texas, and Utah with COVID-19 infection confirmed by reverse transcriptase-polymerase chain reaction testing and lineage classified by whole genome sequencing of specimens self-collected weekly and at COVID-19 illness symptom onset. This analysis was conducted among 1199 participants with SARS-CoV-2 from December 14, 2020, to April 19, 2022, with follow-up until May 9, 2022, reported. Exposures: SARS-CoV-2 lineage (origin strain, Delta variant, Omicron variant) and COVID-19 vaccination status. Main Outcomes and Measures: Clinical outcomes included presence of symptoms, specific symptoms (including fever or chills), illness duration, and medical care seeking. Virologic outcomes included viral load by quantitative reverse transcriptase-polymerase chain reaction testing along with viral viability. Results: Among 1199 participants with COVID-19 infection (714 [59.5%] women; median age, 41 years), 14.0% were infected with the origin strain, 24.0% with the Delta variant, and 62.0% with the Omicron variant. Participants vaccinated with the second vaccine dose 14 to 149 days before Delta infection were significantly less likely to be symptomatic compared with unvaccinated participants (21/27 [77.8%] vs 74/77 [96.1%]; OR, 0.13 [95% CI, 0-0.6]) and, when symptomatic, those vaccinated with the third dose 7 to 149 days before infection were significantly less likely to report fever or chills (5/13 [38.5%] vs 62/73 [84.9%]; OR, 0.07 [95% CI, 0.0-0.3]) and reported significantly fewer days of symptoms (10.2 vs 16.4; difference, -6.1 [95% CI, -11.8 to -0.4] days). Among those with Omicron infection, the risk of symptomatic infection did not differ significantly for the 2-dose vaccination status vs unvaccinated status and was significantly higher for the 3-dose recipients vs those who were unvaccinated (327/370 [88.4%] vs 85/107 [79.4%]; OR, 2.0 [95% CI, 1.1-3.5]). Among symptomatic Omicron infections, those vaccinated with the third dose 7 to 149 days before infection compared with those who were unvaccinated were significantly less likely to report fever or chills (160/311 [51.5%] vs 64/81 [79.0%]; OR, 0.25 [95% CI, 0.1-0.5]) or seek medical care (45/308 [14.6%] vs 20/81 [24.7%]; OR, 0.45 [95% CI, 0.2-0.9]). Participants with Delta and Omicron infections who received the second dose 14 to 149 days before infection had a significantly lower mean viral load compared with unvaccinated participants (3 vs 4.1 log10 copies/µL; difference, -1.0 [95% CI, -1.7 to -0.2] for Delta and 2.8 vs 3.5 log10 copies/µL, difference, -1.0 [95% CI, -1.7 to -0.3] for Omicron). Conclusions and Relevance: In a cohort of US essential and frontline workers with SARS-CoV-2 infections, recent vaccination with 2 or 3 mRNA vaccine doses less than 150 days before infection with Delta or Omicron variants, compared with being unvaccinated, was associated with attenuated symptoms, duration of illness, medical care seeking, or viral load for some comparisons, although the precision and statistical significance of specific estimates varied.

Comparison of a Novel Rapid Lateral Flow Assay to Enzyme Immunoassay Results for Early Diagnosis of Coccidioidomycosis.

BACKGROUND: Coccidioidomycosis (CM) is a common cause of community-acquired pneumonia where CM is endemic. Manifestations include self-limited pulmonary infection, chronic fibrocavitary pulmonary disease, and disseminated coccidioidomycosis. Most infections are identified by serological assays including enzyme-linked immunoassay (EIA), complement fixation, and immunodiffusion. These are time-consuming and take days to result, impeding early diagnosis. A new lateral flow assay (LFA; Sona; IMMY, Norman, OK) improves time-to-result to 1 hour. METHODS: We prospectively enrolled 392 patients with suspected CM, compared the LFA with standard EIA and included procalcitonin evaluation. RESULTS: Compared with standard EIA, LFA demonstrates 31% sensitivity (95% confidence interval [CI], 20-44%) and 92% specificity (95% CI, 88-95%). Acute pulmonary disease (74%) was the most common clinical syndrome. Hospitalized patients constituted 75% of subjects, and compared with outpatients, they more frequently had ≥3 previous healthcare facility visits (P = .05), received antibacterials (P < .01), and had >3 antibacterial courses (P < .01). Procalcitonin (PCT) was <0.25 ng/mL in 52 (83%) EIA-positive patients, suggesting infection was not bacterial. CONCLUSIONS: When CM is a possible diagnosis, LFA identified nearly one-third of EIA-positive infections. Combined with PCT <0.25 ng/mL, LFA could reduce unnecessary antibacterial use by 77%.

Effectiveness of COVID-19 Vaccines in Preventing SARS-CoV-2 Infection Among Frontline Workers Before and During B.1.617.2 (Delta) Variant Predominance - Eight U.S. Locations, December 2020-August 2021.

During December 14, 2020-April 10, 2021, data from the HEROES-RECOVER Cohorts,* a network of prospective cohorts among frontline workers, showed that the Pfizer-BioNTech and Moderna mRNA COVID-19 vaccines were approximately 90% effective in preventing symptomatic and asymptomatic infection with SARS-CoV-2, the virus that causes COVID-19, in real-world conditions (1,2). This report updates vaccine effectiveness (VE) estimates including all COVID-19 vaccines available through August 14, 2021, and examines whether VE differs for adults with increasing time since completion of all recommended vaccine doses. VE before and during SARS-CoV-2 B.1.617.2 (Delta) variant predominance, which coincided with an increase in reported COVID-19 vaccine breakthrough infections, were compared (3,4).

Interim Estimate of Vaccine Effectiveness of BNT162b2 (Pfizer-BioNTech) Vaccine in Preventing SARS-CoV-2 Infection Among Adolescents Aged 12-17 Years - Arizona, July-December 2021.

The BNT162b2 (Pfizer-BioNTech) mRNA COVID-19 vaccine has demonstrated high efficacy in preventing infection with SARS-CoV-2 (the virus that causes COVID-19) in randomized placebo-controlled Phase III trials in persons aged 12-17 years (referred to as adolescents in this report) (1); however, data on real-word vaccine effectiveness (VE) among adolescents are limited (1-3). As of December 2021, the Pfizer-BioNTech vaccine is approved by the Food and Drug Administration (FDA) for adolescents aged 16-17 years and under FDA emergency use authorization for those aged 12-15 years. In a prospective cohort in Arizona, 243 adolescents aged 12-17 years were tested for SARS-CoV-2 by reverse transcription-polymerase chain reaction (RT-PCR) each week, irrespective of symptoms, and upon onset of COVID-19-like illness during July 25-December 4, 2021; the SARS-CoV-2 B.1.617.2 (Delta) variant was the predominant strain during this study period. During the study, 190 adolescents contributed fully vaccinated person-time (≥14 days after receiving 2 doses of Pfizer-BioNTech vaccine), 30 contributed partially vaccinated person-time (receipt of 1 dose or receipt of 2 doses but with the second dose completed <14 days earlier), and 66 contributed unvaccinated person-time. Using the Cox proportional-hazards model, the estimated VE of full Pfizer-BioNTech vaccination for preventing SARS-CoV-2 infection was 92% (95% CI = 79%-97%), adjusted for sociodemographic characteristics, health information, frequency of social contact, mask use, location, and local virus circulation. These findings from a real-world setting indicate that 2 doses of Pfizer-BioNTech vaccine are highly effective in preventing SARS-CoV-2 infection among Arizona adolescents. CDC recommends COVID-19 vaccination for all eligible persons in the United States, including persons aged 12-17 years.