Structural factors associated with SARS-CoV-2 infection risk in an urban slum setting in Salvador, Brazil: A cross-sectional survey

Jerusalem's CoVID-19 Experience-The Effect of Ethnicity on Disease Prevalence and Adherence to Testing

BACKGROUND

The management of the SARS-CoV-2 pandemic depends amongst other factors on disease prevalence in the general population. The gap between the true rate of infection and the detected rate of infection may vary, especially between sub-groups of the population. Identifying subpopulations with high rates of undetected infection can guide authorities to direct resource distribution in order to improve health equity.

METHODS

A cross-sectional epidemiological survey was conducted between April and July 2021 in the Pediatric Emergency Department of the Shaare Zedek Medical Center, Jerusalem, Israel. We compared three categories: unconfirmed disease (UD), positive serology test result with no history of positive PCR; confirmed disease (CD), history of a positive PCR test result, regardless of serology test result; and no disease (ND), negative serology and no history of PCR. These categories were applied to local prevailing subpopulations: ultra-orthodox Jews (UO), National Religious Jews (NRJ), secular Jews (SJ), and Muslim Arabs (MA).

RESULTS

Comparing the different subpopulations groups, MAs and UOs had the greatest rate of confirmed or unconfirmed disease. MA had the highest rate of UD and UO had the highest rate of CD. UD significantly correlated with ethnicity, with a low prevalence in NRJ and SJ. UD was also associated with larger family size and housing density defined as family size per number of rooms.

CONCLUSION

This study highlights the effect of ethnicity on disease burden. These findings should serve to heighten awareness to disease burden in weaker populations and direct a suitable prevention program to each subpopulation's needs. Early awareness and possible intervention may lower morbidity and mortality.

Overestimation of Severe Acute Respiratory Syndrome Coronavirus 2 Household Transmission in Settings of High Community Transmission: Insights From an Informal Settlement Community in Salvador, Brazil

Background

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant has spread globally. However, the contribution of community versus household transmission to the overall risk of infection remains unclear.

Methods

Between November 2021 and March 2022, we conducted an active case-finding study in an urban informal settlement with biweekly visits across 1174 households with 3364 residents. Individuals displaying coronavirus disease 2019 (COVID-19)-related symptoms were identified, interviewed along with household contacts, and defined as index and secondary cases based on reverse-transcription polymerase chain reaction (RT-PCR) and symptom onset.

Results

In 61 households, we detected a total of 94 RT-PCR-positive cases. Of 69 sequenced samples, 67 cases (97.1%) were attributed to the Omicron BA.1* variant. Among 35 of their households, the secondary attack rate was 50.0% (95% confidence interval [CI], 37.0%-63.0%). Women (relative risk [RR], 1.6 [95% CI, .9-2.7]), older individuals (median difference, 15 [95% CI, 2-21] years), and those reporting symptoms (RR, 1.73 [95% CI, 1.0-3.0]) had a significantly increased risk for SARS-CoV-2 secondary infection. Genomic analysis revealed substantial acquisition of viruses from the community even among households with other SARS-CoV-2 infections. After excluding community acquisition, we estimated a household secondary attack rate of 24.2% (95% CI, 11.9%-40.9%).

Conclusions

These findings underscore the ongoing risk of community acquisition of SARS-CoV-2 among households with current infections. The observed high attack rate necessitates swift booster vaccination, rapid testing availability, and therapeutic options to mitigate the severe outcomes of COVID-19.

Extensive transmission of SARS-CoV-2 BQ.1* variant in a population with high levels of hybrid immunity: A prevalence survey

OBJECTIVES

The SARS-CoV-2 BQ.1* variant rapidly spread globally in late 2022, posing a challenge due to its increased immune evasion.

METHODS

We conducted a prevalence survey in Brazil from November 16 to December 22, 2022, as part of a cohort study. We conducted interviews and collected nasal samples for reverse transcription-polymerase chain reaction (RT-PCR) testing and whole-genome sequencing. Cumulative incidence was estimated using RT-PCR positivity, cycle threshold values, and external data on the dynamics of RT-PCR positivity following infection.

RESULTS

Among 535 participants, 54% had documented SARS-CoV-2 exposure before this outbreak and 74% had received COVID-19 vaccination. In this study, 14.8% tested positive for SARS-CoV-2, with BQ.1* identified in 90.7% of cases. Using case data and cycle threshold values, cumulative incidence was estimated at 56% (95% confidence interval, 36-88%). Of the 79 positive participants, 48.1% had a symptomatic illness, with a lower proportion fulfilling the World Health Organization COVID-19 case definition compared to prior Omicron waves. No participants required medical attention.

CONCLUSIONS

Despite high population-level hybrid immunity, the BQ.1* variant attacked 56% of our population. Lower disease severity was associated with BQ.1* compared to prior Omicron variants. Hybrid immunity may provide protection against future SARS-CoV-2 variants but in this case was not able to prevent widespread transmission.

Dynamics of chikungunya virus transmission in the first year after its introduction in Brazil: A cohort study in an urban community

BACKGROUND

The first chikungunya virus (CHIKV) outbreaks during the modern scientific era were identified in the Americas in 2013, reaching high attack rates in Caribbean countries. However, few cohort studies have been performed to characterize the initial dynamics of CHIKV transmission in the New World.

METHODOLOGY/PRINCIPAL FINDINGS

To describe the dynamics of CHIKV transmission shortly after its introduction in Brazil, we performed semi-annual serosurveys in a long-term community-based cohort of 652 participants aged ≥5 years in Salvador, Brazil, between Feb-Apr/2014 and Nov/2016-Feb/2017. CHIKV infections were detected using an IgG ELISA. Cumulative seroprevalence and seroincidence were estimated and spatial aggregation of cases was investigated. The first CHIKV infections were identified between Feb-Apr/2015 and Aug-Nov/2015 (incidence: 10.7%) and continued to be detected at low incidence in subsequent surveys (1.7% from Aug-Nov/2015 to Mar-May/2016 and 1.2% from Mar-May/2016 to Nov/206-Feb/2017). The cumulative seroprevalence in the last survey reached 13.3%. It was higher among those aged 30-44 and 45-59 years (16.1% and 15.6%, respectively), compared to younger (12.4% and 11.7% in <15 and 15-29 years, respectively) or older (10.3% in ≥60 years) age groups, but the differences were not statistically significant. The cumulative seroprevalence was similar between men (14.7%) and women (12.5%). Yet, among those aged 15-29 years, men were more often infected than women (18.1% vs. 7.4%, respectively, P = 0.01), while for those aged 30-44, a non-significant opposite trend was observed (9.3% vs. 19.0%, respectively, P = 0.12). Three spatial clusters of cases were detected in the study site and an increased likelihood of CHIKV infection was detected among participants who resided with someone with CHIKV IgG antibodies.

CONCLUSIONS/SIGNIFICANCE

Unlike observations in other settings, the initial spread of CHIKV in this large urban center was limited and focal in certain areas, leaving a high proportion of the population susceptible to further outbreaks. Additional investigations are needed to elucidate the factors driving CHIKV spread dynamics, including understanding differences with respect to dengue and Zika viruses, in order to guide prevention and control strategies for coping with future outbreaks.

Relationship between clinical-epidemiological parameters and outcomes of patients with COVID-19 admitted to the intensive care unit: a report from a Brazilian hospital

Background

People in low-income countries, especially those with low socio-economic conditions, are likelier to test positive for SARS-CoV-2. The unequal conditions of public health systems also increase the infection rate and make early identification and treatment of at-risk patients difficult. Here, we aimed to characterize the epidemiological profile of COVID-19 patients in intensive care and identify laboratory and clinical markers associated with death.

Materials and methods

We conducted an observational, descriptive, and cross-sectional study in a reference hospital for COVID-19 treatment in the Southern Region of Bahia State, in Brazil, to evaluate the epidemiological, clinical, and laboratory characteristics of COVID-19 patients admitted to the intensive care unit (ICU). Additionally, we used the area under the curve (AUC) to classify survivors and non-survivors and a multivariate logistic regression analysis to assess factors associated with death. Data was collected from the hospital databases between April 2020 and July 2021.

Results

The use of bladder catheters (OR 79.30; p < 0.0001) and central venous catheters (OR, 45.12; p < 0.0001) were the main factors associated with death in ICU COVID-19 patients. Additionally, the number of non-survivors increased with age (p < 0.0001) and prolonged ICU stay (p < 0.0001). Besides, SAPS3 presents a higher sensibility (77.9%) and specificity (63.1%) to discriminate between survivors and non-survivor with an AUC of 0.79 (p < 0.0001).

Conclusion

We suggest that multi-laboratory parameters can predict patient prognosis and guide healthcare teams toward more assertive clinical management, better resource allocation, and improved survival of COVID-19 patients admitted to the ICU.

Blood pressure pattern among blood donors exposed to SARS-CoV-2 in Luanda, Angola: A retrospective study

Background and Aims

SARS-CoV-2 infection is a public health concern. Several aspects related to the pattern of infection remain unclear. This study aimed to investigate the blood pressure pattern among blood donors exposed to SARS-CoV-2 in Luanda, Angola, a sub-Saharan African country.

Methods

We performed a retrospective analysis containing 343 blood donors from December 2019 to September 2020. Parametric tests compared means while χ 2 and logistic regression checked features associated with high blood pressure and were considered significant when p < 0.05.

Results

The mean age of blood donors was 32.2 ± 8.81 years (ranging from 18 to 61 years) and 93% of the men's gender. Overall, 4.7% of the studied population had been exposed to SARS-CoV-2. High blood pressure prevalence increased from unexposed to exposed SARS-CoV-2 (6.7%-18.8%, p = 0.071). SARS-CoV-2 exposure increase systole (131 ± 12.2 mmHg to 136 ± 14.2 mmHg, p = 0.098), diastole (79.9 ± 9.53 mmHg to 84.2 ± 12.7 mmHg, p = 0.086), pulse in beats per minute (72.0 ± 11.1 to 73.7 ± 8.50, p = 0.553), and decrease donating time (6.31 ± 3.72 min to 5.48 ± 1.61 min, p = 0.371). Chances of having high blood pressure were high [OR: 3.20 (95% confidence interval [CI]: 0.85-12.1), p = 0.086] in exposed SARS-CoV-2. Donors exposed to SARS-CoV-2 with abnormal donation time increased from the donor up to 40 years to over 40 years (from 35.7% to 50%, p = 0.696). The mean systolic, diastolic, and pulse pressure were higher for non-O donors (p > 0.05). A significant link was observed, between the Rhesus factor and blood pressure status (p = 0.032).

Conclusion

We showed important variations in blood pressure indices of the Angolan population exposed to SARS-CoV-2. Older age and non-O blood groups appear to be important biological factors for SARS-CoV-2 infection, as well as the risk of developing cardiovascular disease after or during SARS-CoV-2 exposure. Further studies assessing the impact on cardiovascular functions with ongoing or long-term SARS-CoV-2 exposure in individuals from resource-limited countries should be considered.

Correlates of protection for booster doses of the SARS-CoV-2 vaccine BNT162b2

Vaccination, especially with multiple doses, provides substantial population-level protection against COVID-19, but emerging variants of concern (VOC) and waning immunity represent significant risks at the individual level. Here we identify correlates of protection (COP) in a multicenter prospective study following 607 healthy individuals who received three doses of the Pfizer-BNT162b2 vaccine approximately six months prior to enrollment. We compared 242 individuals who received a fourth dose to 365 who did not. Within 90 days of enrollment, 239 individuals contracted COVID-19, 45% of the 3-dose group and 30% of the four-dose group. The fourth dose elicited a significant rise in antibody binding and neutralizing titers against multiple VOCs reducing the risk of symptomatic infection by 37% [95%CI, 15%-54%]. However, a group of individuals, characterized by low baseline titers of binding antibodies, remained susceptible to infection despite significantly increased neutralizing antibody titers upon boosting. A combination of reduced IgG levels to RBD mutants and reduced VOC-recognizing IgA antibodies represented the strongest COP in both the 3-dose group (HR = 6.34, p = 0.008) and four-dose group (HR = 8.14, p = 0.018). We validated our findings in an independent second cohort. In summary combination IgA and IgG baseline binding antibody levels may identify individuals most at risk from future infections.

Seroprevalence of SARS-CoV-2 and Vaccination Coverage among Residents of a Lower-Middle-Class Population in the Federal District, Brazil

Estimating seroprevalence and vaccination coverage against COVID-19 is crucial to the development of well-targeted public health policies at the local level. Here, we estimated seroprevalence and vaccination coverage in a lower-middle-class population in Brazil. We conducted an observational, cross-sectional, population-based survey from 24 September to 19 December 2021. CMIA tests were used to detect anti-SARS-CoV-2 IgG against the N-protein. The overall seroprevalence was 24.15% (177/733), and vaccination coverage was 91.40% (670/733); 72.09% (483/670) were fully vaccinated. Among vaccinated participants, seroprevalence was 24.77% (95% CI 21.50-28.04; 166/670), with a prevalence ratio (PR) of 1.03 (95% CI 0.98-1.08; p-value 0.131). Among participants who received an mRNA vaccine with S-based epitope (485), seroprevalence was 16.29% (95% CI 13.04-19.85; 79/485). Among unvaccinated participants, seroprevalence was 17.46% (95% CI 10.04-28.62; 11/63). Finally, in spite of the political climate and other possible causes for vaccine hesitancy, the positive Brazilian culture towards vaccination might have curbed hesitancy.