Evaluation of viral loads in patients with SARS-CoV-2 Delta variant infection: Higher loads do not translate into different testing scenarios

The Delta SARS-CoV-2 variant is very infectious, and it is spreading quickly during this pandemic. In the study, we compared viral loads in surging cases infected with the SARS-CoV-2 Delta variant in the fourth wave of COVID-19 with the three prior waves. The data comprised viral loads from positive cases detected within the UPMC health care system in Allegheny County, Pennsylvania. A total of 2,059 upper airway samples were collected and tested for SARS-CoV-2 positive by RT-PCR during March 2020-September 2021. We did not observe significant difference in viral load difference between the third (December 2020 - January 2021) and fourth (June 2021 - September 2021) waves; however, they had the higher viral load than the first (March 2020 - June 2020) and second waves (June 2020 - August 2020). We did find an age-related effect with the elderly presenting with lower viral loads, which was also seen in the earlier waves. However, the level of viral load in the fourth wave was not sufficient higher to qualitatively change our expected detected rates using various testing modalities.

Examining Sexual Orientation Differences in the Utilization of the Human Papillomavirus Vaccine, Human Papillomavirus Test, and Cervical Papanicolaou Test in Allegheny County, Pennsylvania

Despite sexual minorities' (SMs) increased risk for contracting human papillomavirus (HPV) and developing related cancers compared to their heterosexual peers, we know little about SM disparities in uptake of HPV vaccines and routine screenings. Therefore, this study examined sexuality differences in HPV preventive interventions and related screenings. From 2015 to 2016, Pennsylvania's Allegheny County Health Department commissioned a health survey of 9,026 adults in their catchment area using probability-based sampling. Multivariable models tested differences by sexual identity separately for cisgender men and women (heterosexual versus gay/lesbian, bisexual, and other) for lifetime receipt of HPV vaccine and number of HPV vaccines. Among women, we examined sexuality differences in HPV and cervical Pap tests, adjusting for age, race/ethnicity, education, marital status, and income. No differences in prevention utilization emerged when comparing heterosexual women to all SM women. However, exploratory analyses comparing heterosexual women to subgroups of SM women found lesbians had higher odds (adjusted odds ratio [AOR] = 5.27; 95% confidence interval [CI] = 1.15–24.09) of never receiving an HPV vaccine. Women who reported their sexuality as “other” had higher odds (AOR = 5.65; 95% CI = 1.03–31.02) of never receiving a cervical Pap test compared to heterosexual women. “Other” women had higher odds (AOR = 19.80; 95% CI = 1.64–239.16) of never receiving a cervical Pap test when compared to heterosexual women receiving one within the recommended screening guidelines. SM men's utilization was not significantly different from heterosexual men, though vaccination uptake for both groups was low. These findings highlight the need for additional public health surveillance to understand cancer prevention utilization among this underserved population.

A Cross-Sectional Study of SARS-CoV-2 Seroprevalence between Fall 2020 and February 2021 in Allegheny County, Western Pennsylvania, USA

Seroprevalence studies are important for understanding the dynamics of local virus transmission and evaluating community immunity. To assess the seroprevalence for SARS-CoV-2 in Allegheny County, an urban/suburban county in Western PA, 393 human blood samples collected in Fall 2020 and February 2021 were examined for spike protein receptor-binding domain (RBD) and nucleocapsid protein (N) antibodies. All RBD-positive samples were evaluated for virus-specific neutralization activity. Our results showed a seroprevalence of 5.5% by RBD ELISA, 4.5% by N ELISA, and 2.5% for both in Fall 2020, which increased to 24.7% by RBD ELISA, 14.9% by N ELISA, and 12.9% for both in February 2021. Neutralization titer was significantly correlated with RBD titer but not with N titer. Using these two assays, we were able to distinguish infected from vaccinated individuals. In the February cohort, higher median income and white race were associated with serological findings consistent with vaccination. This study demonstrates a 4.5-fold increase in SARS-CoV-2 seroprevalence from Fall 2020 to February 2021 in Allegheny County, PA, due to increased incidence of both natural disease and vaccination. Future seroprevalence studies will need to include the effect of vaccination on assay results and incorporate non-vaccine antigens in serological assessments.

Rescaling and Small Area Estimation of Health Survey Data as applied to Smoking Rates in Allegheny County, Pennsylvania

We propose a novel, two-step method for rescaling health survey data and creating small area estimates of smoking rates using a Behavioral Risk Factor Surveillance System (BRFSS) survey administered in 2015 to participants living in Allegheny County, in the state of Pennsylvania, USA. The first step consisted of a spatial microsimulation to rescale location of survey respondents from zip codes to tracts based on census population distributions by age, sex, race, and education. The rescaling allowed us, in the second step, to utilize and select from available census tract specific ancillary data on social vulnerability for small area estimation (SAE) of local health risk using an area level version of a logistic linear mixed model. To demonstrate this new two-step algorithm, we estimated the ever-smoking rate for the census tracts of Allegheny County. The ever-smoking rate was slightly above 70% for two census tracts to the southeast of the city of Pittsburgh. Several tracts in the southern and eastern sections of Pittsburgh also had relatively high (>65%) ever-smoking rates. These small area estimates may be used in local public health efforts to target interventions and educational resources aimed at reducing cigarette smoking. Further, our new two-step methodology may be extended to small area estimation for other locations, and other health-related behaviors and outcomes.

Predicting virologically-confirmed influenza using school absences in Allegheny County, Pennsylvania, USA during the 2007-2015 influenza seasons

Background Children are important in community-level influenza transmission. School-based monitoring may inform influenza surveillance. Methods We used reported weekly confirmed influenza in Allegheny County during the 2007, and 2010-2015 influenza seasons using Pennsylvania’s Allegheny County Health Department all-age influenza cases from health facilities, and all-cause and influenza-like illness (ILI)-specific absences from nine county school districts. Negative binomial regression predicted influenza cases using all-cause and illness-specific absence rates, calendar week, average weekly temperature and relative humidity, using four cross-validations. Results School districts reported 2,184,220 all-cause absences (2010-2015). Three one-season studies reported 19,577 all-cause and 3,012 ILI-related absences (2007, 2012, 2015). Over seven seasons, 11,946 confirmed influenza cases were reported. Absences improved seasonal model fits and predictions. Multivariate models using elementary school absences outperformed middle and high school models (relative mean absolute error (relMAE)=0.94, 0.98, 0.99). K-5 grade-specific absence models had lowest mean absolute errors (MAE) in cross-validations. ILI-specific absences performed marginally better than all-cause absences in two years, adjusting for other covariates, but markedly worse one year. Conclusions Our findings suggest seasonal models including K-5th grade absences predict all-age confirmed influenza and may serve as a useful surveillance tool.