ABSTRACT
Background: Although data are mixed, most cohorts show a similar or lower COVID-19 incidence among people living with HIV (PLWH) compared to the general population. However, incidence may be impacted by lower testing rates among vulnerable populations. We compared SARS-CoV-2 seroprevalence and IgG levels, and disease severity, among patients with and without HIV receiving care within a county hospital system over a three-month period. Methods: From August through October 2020, remnant serum samples were collected from all PLWH who underwent routine outpatient laboratory testing at San Francisco General Hospital which houses a large HIV clinic (Ward 86). Patients with HIV were matched on time of collection (same day) and age (+/- 5 years) to 1-2 adults without HIV. SARS-CoV-2 levels of IgG levels was quantified in serum using the Pylon IgG assay (100% specificity on internal validation). Seroprevalence was compared by HIV status via conditional logit models, adjusting for sex. For those with reactive results, IgG levels were compared by HIV status using log-transformed generalized estimating equations. Severe disease, assessed via chart review, was defined as requiring oxygen. Results: Among 1,411 individuals (46% PLWH), the median age was 58 (IQR: 49-65), 64% were men. COVID-19 seroprevalence was 3.1% among PLWH compared to 6.8% among people without HIV (adjusted odds ratio 0.41;95% confidence interval (CI): 0.25-0.68, p<0.001). Among those with reactive COVID-19 IgG results (n=72, 20 in PLWH);antibody levels were 47% lower among PLWH (95% CI: 19-65% lower;p=0.003;Figure);however, there was a trend towards higher disease severity among PLWH [15% (n=3) vs. 4% (n=2);p=0.13]. Conclusion: Both seroprevalence, and absolute SARS-CoV-2 IgG levels in those with reactive results, were lower among PLWH, within a time and agematched population of outpatients receiving routine laboratory testing in an urban hospital. PLWH may have had higher adherence to non-pharmaceutical interventions (NPIs) than those without HIV, leading to lower COVID-19 seroprevalence and, possibly, lower COVID-19 IgG levels if infected with a lower viral inoculum due to NPIs. Alternatively, PLWH may mount lower antibody responses to SARS-CoV-2, as has been demonstrated with hepatitis B and yellow fever vaccines. Further studies of COVID-19 susceptibility and immunity are needed among PLWH. Moreover, PLWH should be enrolled in SARS-CoV-2 vaccine studies or followed after vaccination to ensure they mount sufficient humoral responses.
ABSTRACT
Background: Most diagnostic tests for SARS-CoV-2, the causative agent of COVID-19, are RT-PCR based. This method is sensitive but cannot distinguish replicating from non-replicating virus. RT-PCR cycle threshold (Ct) values are inversely correlated with viral load, and higher Ct values have been correlated with lower in vitro viral infectivity. However, relatively few data exist on the association between Ct values and patients' duration of symptoms remains unclear. We thus evaluated Ct values and symptom duration in a cohort of patients hospitalized with COVID-19. Methods: We assessed all patients admitted to San Francisco General Hospital between April 1 and May 18, 2020 with confirmed COVID-19 infection based on RT-PCR testing (Abbott m2000 platform). We included patients having diagnostic testing for suspected COVID-19 and patients having asymptomatic testing per hospital policy. For symptomatic patients, date of symptom onset was abstracted from hospital records, and time from symptom onset to test date was calculated. RT-PCR Ct values were manually extracted. Median Ct and IQR were calculated for patients with < 10 days of symptoms, ≥10 days of symptoms, and asymptomatic disease. Betweengroup comparisons were performed using the Kruskal-Wallis test. Results: Among 61 patients with positive RT-PCR tests, 40 patients reported < 10 days of symptoms at the time of testing, 15 reported ≥10 days of symptoms, and 6 were asymptomatic. The median Ct value was 14.2 cycles (IQR, 10.2, 18.3) among patients reporting < 10 days of symptoms, 19.7 cycles (IQR, 15.3, 23.9) among patients reporting ≥10 days of symptoms, and 26.3 (IQR, 25.0, 29.1) among asymptomatic patients. Ct values were significantly lower among patients with < 10 days of symptoms compared to patients with >=10 days of symptoms (p=0.01) and when compared to asymptomatic patients (p=0.0002) [Figure]. Conclusion: SARS-CoV-2 RT-PCR cycle threshold values were higher (indicating lower viral load) in patients with longer symptom duration and were highest in asymptomatic patients. These results add to emerging data suggesting that strategies for optimal isolation of patients in both community and hospital settings could be informed by a combination of symptom duration and RT-PCR Ct values. (Table Presented).