High prevalence of anti-SARS-CoV-2 IgG antibody in the Xikrin of Bacajá (Kayapó) indigenous population in the brazilian Amazon

Host genetics and the profile of COVID-19 in indigenous people from the Brazilian Amazon: A pilot study with variants of the ACE1, ACE2 and TMPRSS2 genes

This pilot study aimed to investigate genetic factors that may have contributed to the milder clinical outcomes of COVID-19 in Brazilian indigenous populations. 263 Indigenous from the Araweté, Kararaô, Parakanã, Xikrin do Bacajá, Kayapó and Munduruku peoples were analyzed, 55.2% women, ages ranging from 10 to 95 years (average 49.5 ± 20.7). Variants in genes involved in the entry of SARS-CoV-2 into the host cell (ACE1 rs1799752 I/D, ACE2 rs2285666 C/T, ACE2 rs73635825 A/G and TMPRSS2 rs123297605 C/T), were genotyped in indigenous peoples from the Brazilian Amazon, treated during the SARS-CoV-2 pandemic between 2020 and 2021. The distribution of genotypes did not show any association with the presence or absence of IgG antibodies. Additionally, the influence of genetic variations on the severity of the disease was not examined extensively because a significant number of indigenous individuals experienced the disease with either mild symptoms or no symptoms. It is worth noting that the frequencies of risk alleles were found to be lower in Indigenous populations compared to both continental populations and Brazilians. Indigenous Brazilian Amazon people exhibited an ethnic-specific genetic profile that may be associated with a milder disease, which could explain the unexpected response they demonstrated to COVID-19, being less impacted than Brazilians.

Seroprevalence Of SARS-COV-2 infection in asymptomatic indigenous from the largest Brazilian periurban area

This study assessed the seroprevalence of SARS-CoV-2 in 496 asymptomatic individuals from Mato Grosso do Sul, located in Dourados, the largest periurban indigenous area in Brazil, from January 25 to February 4, 2021. The volunteers participated before receiving their first dose of the CoronaVac inactivated vaccine. For screening, blood samples were collected and analyzed using SARS-CoV-2 rapid tests and the enzyme-linked immunosorbent assay (ELISA). We observed varying trends in total anti-SARS-CoV-2 antibodies across different variables. Seropositivity among the participants tested was 63.70% (316/496) using the rapid test and 52.82% (262/496) were positive using the ELISA method. The majority of participants identified with the Guarani-Kaiowá ethnic group, with 66.15% (217/328), and other ethnic groups with 58.84% (193/328). The median age of the subjects was 30.5 years, with 79.57% (261/328) being femaleThis research showed the elevated seroprevalence of SARS-CoV-2 antibodies in asymptomatic Brazilians. The findings indicate a high seropositivity rate among the asymptomatic indigenous population of Midwest Brazil. This underscores the overlooked status of these communities and underscores the need for targeted national initiatives that emphasize the protection of vulnerable ethnic groups in the fight against COVID-19.

Humoral immune response to SARS-CoV-2 and endemic coronaviruses in urban and indigenous children in Colombia

BACKGROUND

Although anti-SARS-CoV-2 humoral immune responses and epidemiology have been extensively studied, data gaps remain for certain populations such as indigenous people or children especially in low- and middle-income countries. To address this gap, we evaluated SARS-CoV-2 seroprevalence and humoral immunity towards the parental B.1 strain, local SARS-CoV-2 variants, and endemic coronaviruses in children from Colombia from March to April 2021.

METHODS

We performed a cross-sectional seroprevalence study with 80 children from Bogotá and expanded our analysis by comparing results with an independent observational study of 82 children from the Wiwa community living in the north-eastern Colombian territories. Antibody IgG titers towards SARS-CoV-2 and the endemic coronaviruses as well as ACE2 binding inhibition as a proxy for neutralization towards several SARS-CoV-2 variants were analyzed using two multiplex-based immunoassays.

RESULTS

While we find seroprevalence estimates of 21.3% in children from Bogotá, seroprevalence is higher with 34.1% in Wiwa children. We observe a robust induction of antibodies towards the surface-exposed spike protein, its S1-, S2- and receptor-binding-subdomains in all SARS-CoV-2 seropositive children. Only nucleocapsid-specific IgG is significantly lower in the indigenous participants. ACE2 binding inhibition is low for all SARS-CoV-2 variants examined. We observe a dominance of NL63 S1 IgG levels in urban and indigenous children which suggests an early exposure to this respiratory virus independent of living conditions and geographic location. SARS-CoV-2 seropositivity does not correlate with antibody levels towards any of the four endemic coronaviruses indicating the absence of cross-protective immunity.

CONCLUSIONS

Overall, antibody titers, but in particular ACE2 binding inhibition are low within Colombian samples, requiring further investigation to determine any potential clinical significance.

Severe Acute Respiratory Syndrome (SARS) in the Context of the COVID-19 Pandemic Among Indigenous Peoples of Brazil: Epidemiology and Risk Factors Associated with Death

INTRODUCTION

Severe Acute Respiratory Syndrome (SARS) represents a serious public health problem for the indigenous peoples of Brazil, since acute respiratory infections are the main causes of morbidity and mortality in this population.

OBJECTIVE

To assess cases of SARS in Brazilian indigenous peoples in the context of the COVID-19 pandemic, as well as sociodemographic and health factors associated with deaths from SARS in this population.

METHODS

Ecological study carried out based on secondary data from the Brazilian Database for Epidemiological Surveillance of Influenza referring to the Brazilian indigenous population with SARS in 2020. The variables included sociodemographic factors and health conditions. Statistical analyses were carried out considering absolute (n) and relative (%) frequencies and logistic regression with odds ratios (OR), with death as the outcome of interest.

RESULTS

A total of 3062 cases were reported in the analyzed period. Of these, there was a predominance of men (54.6%), adults (41.4%), with comorbidities (52.3%), with low levels of schooling (67.4%) and residents of rural areas (55.8%). Cases and deaths were concentrated in the states of Amazonas and Mato Grosso do Sul, states in the North and Midwest of Brazil. A greater chance of death was observed in elderly indigenous people (OR = 6.29; 95%CI 4.71-8.39), with low levels of schooling (OR = 1.72; 95%CI 1.22-2.28), residents of rural areas (OR = 1.35; 95%CI 1.12-1.62), and with comorbidities (OR = 1.87; 95%CI 1.42-2.46), especially obesity (OR = 2.56; 95%CI 1.07-6.11).

CONCLUSION

The study was able to trace the clinical-epidemiological profile, as well as identify the groups of indigenous people most vulnerable to SARS as a result of COVID-19 and evolution to death in Brazil. The findings show the high impact on the morbidity and mortality of the Brazilian indigenous population exposed to SARS and are relevant for epidemiological health surveillance, since they can guide preventive public policy actions and quality of life measures for this ethnic group in Brazil.

Seroprevalence of SARS-CoV-2 in Brazil: A systematic review and meta-analysis

OBJECTIVES

To summarize the data on SARS-CoV-2 seroprevalence surveys conducted in Brazil before the introduction of vaccines METHODS: The authors conducted a systematic review and meta-analysis on the seroprevalence of SARS-CoV-2 infection in Brazil. The present review followed the PRISMA guidelines. The authors searched Medline, Embase, and LILACS databases for serologic surveys conducted in the Brazilian population, in the period from 01/10/2019 to 07/11/2021, without language restrictions. The authors included studies that presented data concerning SARS-CoV-2 antibodies seroprevalence in Brazil and had a sample size ≥50 individuals. Considering the expected heterogeneity between studies, all analyses were performed using the random effects model, and heterogeneity was assessed using the I² statistic RESULTS: Of 586 publications identified in the initial searches, 54 were included in the review and meta-analysis, which contained the results of 135 surveys, with 336,620 participants. The estimated seroprevalence was 11.0%, ranging from 1.0% to 83.0%, with a substantial heterogeneity (I² = 99.55%). In subgroup analyses, the authors observed that the prevalence of SARS-CoV-2 antibodies was 13.0% in blood donors, 9.0% in the population-based surveys, 13% in schoolchildren, and 11.0% in healthcare workers.

CONCLUSIONS

Seroprevalence increases over time. Large differences were observed among the regions of the country. It was higher in the Northern region, decreasing towards the South. The present results may contribute to the analysis of the spread of SARS-CoV-2 infection in the Brazilian population before vaccination, one of the factors that may be influencing the clinical presentation of COVID-19 cases related to the new variants, as well as the effectiveness of the vaccination program.

COVID-19 vaccination, incidence, and mortality rates among indigenous populations compared to the general population in Brazil: Describing trends over time

Background

Chronic social and health inequities faced by indigenous peoples in Brazil foretell the detrimental impact of COVID-19.

Methods

We use de-identified, publicly available data from the Ministry of Health from March/2020 - December/2021 to describe vaccination coverage, cumulative incidence, and cumulative mortality rates due to COVID-19 among indigenous peoples. We also compare vaccination coverage among indigenous peoples with that reported for older adults, who were simultaneously included as a priority group in the vaccination strategy. Finally, we compared COVID-19 incidence and mortality rates in the indigenous population with that reported for the general Brazilian population.

Findings

We found important heterogeneities in vaccination coverage across the 34 indigenous districts, and a lower overall coverage among indigenous peoples compared to older adults. We observed higher COVID-19 cumulative incidence rates among indigenous populations compared to the general Brazilian population. Although mortality rates were seemingly lower, data should be interpreted with caution due to a younger age structure and more frequent underreporting of cases and deaths among indigenous populations. After the beginning of COVID-19 vaccination program, we observed a decrease in both incidence and mortality rates among indigenous peoples in all Brazilian regions.

Interpretation

The COVID-19 pandemic has had a heavy toll on vulnerable populations. Although social and geographic isolation challenges the implementation of any vaccination program for indigenous populations, prior experience suggests that the COVID-19 vaccination strategy lacked effectiveness. The absence of a coordinated strategy to reinforce the importance of the vaccine and other prevention methods, to guarantee the access to trustworthy information, and to respond with the necessary resources in extreme situations, resulted in lower COVID-19 vaccination coverage, higher incidence rates, and preventable deaths due to COVID-19 among indigenous peoples in Brazil.

Funding

This work was not supported by specific funding.

COVID-19 and outpatient care: a nationwide household survey

We aimed to assess the proportion of the population in 133 Brazilian municipalities who - from March to August 2020 - had a health problem but failed to seek care or failed to attend to a health service for routine appointment or examination. We conducted a household survey from August 24-27 in 133 Brazilian cities by asking the subjects if, since the beginning of the COVID-19 pandemic in March 2020, they had suffered from a health problem but did not seek care or failed to attend to a routine or screening examination. Poisson regression was used for the analyses. We interviewed 33,250 subjects and 11.8% (95%CI: 11.4-12.1) reported that, since March 2020, they failed to seek care despite being ill, 17.3% (95%CI: 16.9-17.7) failed to attend to a routine or screening examination and 23.9% (95%CI: 23.4-24.4) reported one or both outcomes. Health service closure and fear of the COVID-19 infection were the main reasons for not seeking care. Women and the poorest were more likely to not look for a health service, despite having a health problem or a scheduled routine appointment. On the other hand, those subjects who self-identified as white were less likely to not look for a health service. The COVID-19 pandemic is more critical for the indigenous people and the poorest, and these people are also more likely to not seek care for other health conditions during the pandemic.

Severe Acute Respiratory Syndrome by SARS-CoV-2 Infection or Other Etiologic Agents Among Brazilian Indigenous Population: An Observational Study from the First Year of Coronavirus Disease (COVID)-19 Pandemic

Background

Indigenous peoples are vulnerable to pandemics, including to the coronavirus disease (COVID)-19, since it causes high mortality and specially, the loss of elderly Indigenous individuals.

Methods

The epidemiological data of severe acute respiratory syndrome (SARS) by SARS-CoV-2 infection or other etiologic agents (OEA) among Brazilian Indigenous peoples during the first year of COVID-19 pandemic was obtained from a Brazilian Ministry of Health open-access database to perform an observational study. Considering only Indigenous individuals diagnosed with SARS by COVID-19, the epidemiology data were also evaluated as risk of death. The type of sample collection for virus screening, demographic profile, clinical symptoms, comorbidities, and clinical evolution were evaluated. The primary outcome was considered the death in the Brazilian Indigenous individuals and the secondary outcome, the characteristics of Brazilian Indigenous infected by SARS-CoV-2 or OEA, as the need for intensive care unit admission or the need for mechanical ventilation support. The statistical analysis was done using Logistic Regression Model. Alpha of 0.05.

Findings

A total of 3,122 cases of Indigenous individuals with SARS in Brazil were reported during the first year of the COVID-19 pandemic. Of these, 1,994 were diagnosed with COVID-19 and 730/1,816 (40.2%) of them died. The death rate among individuals with SARS-CoV-2 was three-fold increased when compared to the group of individuals with OEA. Several symptoms (myalgia, loss of smell, and sore throat) and comorbidities (cardiopathy, systemic arterial hypertension, and diabetes mellitus) were more prevalent in the COVID-19 group when compared to Indigenous individuals with OEA. Similar profile was observed considering the risk of death among the Indigenous individuals with COVID-19 who presented several symptoms (oxygen saturation <95%, dyspnea, and respiratory distress) and comorbidities (renal disorders, cardiopathy, and diabetes mellitus). The multivariate analysis was significant in differentiating between the COVID-19-positive and non-COVID-19 patients [X²₍₇₎=65.187; P-value<0.001]. Among the patients’ features, the following contributed in relation to the diagnosis of COVID-19: age [≥43 years-old [y.o.]; OR=1.984 (95%CI=1.480-2.658)]; loss of smell [OR=2.373 (95%CI=1.461-3.854)]; presence of previous respiratory disorders [OR=0.487; 95%CI=0.287-0.824)]; and fever [OR=1.445 (95%CI=1.082-1.929)]. Also, the multivariate analysis was able to predict the risk of death [X²₍₉₎=293.694; P-value<0.001]. Among the patients’ features, the following contributed in relation to the risk of death: male gender [OR=1.507 (95%CI=1.010-2.250)]; age [≥60 y.o.; OR=3.377 (95%CI=2.292-4.974)]; the need for ventilatory support [invasive mechanical ventilation; OR=24.050 (95%CI=12.584-45.962) and non-invasive mechanical ventilation; OR=2.249 (95%CI=1.378-3.671)]; dyspnea [OR=2.053 (95%CI=1.196-3.522)]; oxygen saturation <95% [OR=1.691 (95%CI=1.050-2.723)]; myalgia [OR=0.423 (95%CI=0.191-0.937)]; and the presence of kidney disorders [OR=3.135 (95%CI=1.144-8.539)].

Interpretation

The Brazilian Indigenous peoples are in a vulnerable situation during the COVID-19 pandemic and presented an increased risk of death due to COVID-19. Several factors were associated with enhanced risk of death, as male sex, older age (≥60 y.o.), and need for ventilatory support; also, other factors might help to differentiate SARS by COVID-19 or by OEA, as older age (≥43 y.o.), loss of smell, and fever.

Funding

Fundação de Amparo à Pesquisa do Estado de São Paulo (Foundation for Research Support of the State of São Paulo; #2021/05810-7).

Anti-SARS-CoV-2 antibodies among indigenous populations of the Brazilian Amazon: a cross-sectional study

OBJECTIVES

The emergence of SARS-CoV-2 and its pandemic spread generated serious concern about the impact of the infection on vulnerable indigenous populations of the Brazilian Amazon. Thus, this study aimed to perform a seroepidemiological survey of anti-SARS-CoV-2 antibodies in those populations.

SETTING

Six indigenous ethnic groups living in the State of Pará (Northern Brazil) were investigated. The villages of Xikrin do Bacajá, Assurini, Araweté, Parakanã, Munduruku and Kararaô were visited from October 2020 to January 2021.

DESIGN AND PARTICIPANTS

We performed a cross-sectional study to investigate the prevalence of anti-spike (S1) IgG antibodies. Plasma was tested for the presence of anti-SARS-CoV-2 IgM and IgG antibodies using two assays (a lateral flow rapid test and an ELISA). A total of 1185 individuals of both sexes were enrolled in the study.

RESULTS

The prevalences of IgM and IgG antibodies were 6.9% and 68.1%, respectively, ranging from 0% to 79.6%, with significant differences (p<0.001) between age groups in three communities (Araweté, Xikrin and Munduruku) and a virulence rate of 0.86%. The overall IgG prevalence obtained by rapid tests and ELISAs were similar, and the agreement of the results between the two tests was 80%, which was classified as good (kappa=0.4987; p<0.001; sensitivity of 82.1% and specificity of 71.6%). Herd immunity was probably attained, similar to that found in other communities of the Amazon.

CONCLUSIONS

SARS-CoV-2 spread rapidly among the indigenous populations investigated, but it had a low mortality rate. It is necessary to expand serological investigations to other communities in the Amazon region of Brazil.

Seroprevalence and lethality by SARS-CoV-2 in indigenous populations of Latin America and the Caribbean: a systematic review

Background

Latin America and the Caribbean (LAC) has presented some of the highest numbers of cases and deaths due to COVID-19 in the world. Even though indigenous communities represent 8% of the total population in this region, the impact of COVID-19 on this historically vulnerable population has only been briefly explored. Thus, this study aimed to estimate the seroprevalence and lethality attributable to SARS-CoV-2 in the indigenous population of LAC.

Methods

A systematic review was conducted utilizing multiple databases (registry PROSPERO: CRD42020207862). Studies published in English, Spanish or Portuguese were selected between December 1st, 2019, and April 14^th, 2021. The evaluation of the quality of the study was carried out utilizing the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. A qualitative synthesis of the data analyzed was conducted following the MOOSE and PRISMA declarations.

Results

Fifteen studies met the inclusion criteria. Eleven studies were carried out in a Brazilian population, three in a Mexican population, and one in a Colombian population. Four studies reported data about the seroprevalence of SARS-CoV-2 in indigenous populations of Brazil (range: 4.2–81.65%). Twelve studies reported lethality in indigenous people (eight in Brazil, three in Mexico, and one in Colombia). In Brazil, a lethality of 53.30% was described in a hospital setting and between 1.83% and 4.03% in community studies. In Mexico, the lethality of COVID-19 ranged between 16.5% and 19.9%. Meanwhile, in Colombia, a lethality of 3.41% was reported. Most studies were deemed to be of good quality.

Conclusions

Despite COVID-19 affecting indigenous populations of LAC, there is limited evidence of the seroprevalence and lethality of the infection by SARS-CoV-2 in this population. Future investigations should ensure standardized methods that allow comparability among studies and ensure the precision of the results obtained.

Retrospective epidemiology of the SARS-CoV-2 (and COVID-19) epidemic among 27 Brazilian cities

Background

Most of the countries facing the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic are still trying to understand the dynamics of the behavior of the virus and dissemination of the new agent.

Objectives

A retrospective descriptive epidemiological study of the 26 state capitals of Brazil and its capital, Brasilia, was performed to investigate the behavior of the infection and disease caused by SARS-CoV-2.

Study design

The data presented were obtained from the State Health Departments and the Brazilian Ministry of Health. Seven epidemiological markers (including the incidence, mortality and case fatality rates and the growth of the epidemic measured by the ratios observed on days 30, 60 and 90) were compared for the initial 90 days of the epidemic for each city.

Results

The epidemic spread to the country within 25 days, and deaths occurred as early as nine days from initiation. The incidence and mortality rates ranged from 70 to almost 1,599/100,000 and less than 1 to 1,171/1,000,000, respectively, at the end of the 90-day period of observation. The CFR was less than two up to 12.31%. The magnitude of each marker clustered the cities in different groups. The epidemic was managed differently in each city, with differences in qualified medical services and medical preparedness to face the emergency situation.

Conclusions

Although modeling the epidemic has been a constant task, epidemiological data should be pursued to define actual information, such as the prevalence and incidence rates, to understand the unpredictable nature of this emerging infection, including the present policy of vaccination campaigns.

Migration in times of pandemic: SARS-CoV-2 infection among the Warao indigenous refugees in Belém, Pará, Amazonia, Brazil

Background

The emergence of the new causative agent of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in the city of Wuhan, China, in December 2019, and its spread worldwide, led the World Health Organization (WHO) to declare a pandemic. The disease has caused high mortality among traditional populations and the most socially vulnerable groups such indigenous and refugees. The present study aims to investigate the prevalence of anti-SARS-CoV-2 IgG antibodies in the population of Venezuelan indigenous Warao refugees residing in private and public shelters in the city of Belem, capital of Para State, in the Brazilian Amazon.

Methods

One hundred one individuals of both sexes (43 men and 58 women) with ages varying from 18 to 77 years (average of 36 years) were investigated. Whole blood samples were collected and subsequently separated into plasma and leukocytes. Serological analysis was performed using an enzyme-linked immunosorbent assay - ELISA (Anti-SARS-COV-2 S1 IgG, EUROIMMUN, USA).

Results

The results indicate a positive serum prevalence of 83.2% (84), of which 77.6% (45/58) were females and 90.7% (39/43) were males. An indeterminate profile was observed in 6.9% (7), where it was not possible to confirm the presence of antibodies, and 9.9% (10) individuals were negative for IgG antibodies.

Conclusions

The finding of the high seroprevalence of IgG anti-SARS-CoV-2 antibodies reveals a high exposure of the Warao population in Belem to infection with the new coronavirus. These results underscore the importance of maintaining epidemiological surveillance with testing in traditional populations due to the high possibility of spreading the virus, especially among the most socioeconomically vulnerable groups, which depend exclusively on the Unified Health System (SUS), such as refugees and indigenous people.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-11696-7.

Increased vulnerability to SARS-CoV-2 infection among indigenous people living in the urban area of Manaus

The COVID-19 pandemic threatens indigenous peoples living in suburban areas of large Brazilian cities and has thus far intensified their pre-existing socio-economic inequalities. We evaluated the epidemiological situation of SARS-CoV-2 infection among residents of the biggest urban multiethnic indigenous community of the Amazonas state, Brazil. Blood samples of 280 indigenous people living in the surrounding area of Manaus were tested for the presence of anti-SARS-CoV-2 IgA or IgG antibodies. The risk factors and sociodemographic information were assessed through an epidemiological questionnaire. We found a total positivity rate of 64.64% (95% CI 59.01–70.28) for SARS-CoV-2 infection. IgA and IgG were detected in 55.71% (95% CI 49.89–61.54) and 60.71% (95% CI 54.98–66.45) of the individuals, respectively. Over 80% of positive individuals were positive for both IgA and IgG.No significant difference in positivity rates between genders or age groups was observed. Moreover, the age group ≥ 60 years old showed the highest antibody ratios (IgA mean ratio = 3.080 ± 1.623; IgG mean ratio = 4.221 ± 1.832), while the age groups 13–19 and 20–29 showed the lowest IgA (mean ratio = 2.268 ± 0.919) and IgG ratios (mean ratio = 2.207 ± 1.246), respectively. Individuals leaving the home more frequently were at higher risk of infection (Odds ratio (OD) 2.61; 95% CI 1.00–1.49; p = 0.048). Five or more individuals per household increased fivefold the risk of virus transmission (OR 2.56; 95% CI 1.09–6.01; p = 0.019). The disproportionate dissemination of SARS-CoV-2 infection observed among the study population might be driven by typical cultural behavior and socioeconomic inequalities. Despite the pandemic threat, this population is not being targeted by public policies and appears to be chronically invisible to the Brazilian authorities.

The potential for vaccination-induced herd immunity against the SARS-CoV-2 B.1.1.7 variant

We assess the feasibility of reaching the herd immunity threshold against SARS-CoV-2 through vaccination, considering vaccine effectiveness (VE), transmissibility of the virus and the level of pre-existing immunity in populations, as well as their age structure. If highly transmissible variants of concern become dominant in areas with low levels of naturally-acquired immunity and/or in populations with large proportions of < 15 year-olds, control of infection without non-pharmaceutical interventions may only be possible with a VE ≥ 80%, and coverage extended to children.