Scientific knowledge about infections by the new coronavirus in older adults : a scoping review

e20200938 http://dx.doi.org/10.1590/0034-7167-2020-0938 12 of ABSTRACT Objective: to map the scientific knowledge about COVID-19 in older adults. Method: this is a scoping review literature review. A search was performed in the PubMed, CINAHL, Web of Science and LILACS databases. Original articles that answered the guiding question were included: what scientific knowledge is available in the world about COVID-19 in older adults? Results: thirty-one articles were included, most of them carried out in China (n=23) and with a retrospective design (n=13) and case studies/case series (n=13). Based on the findings, six thematic categories emerged: clinical signs and symptoms (n=12), other information (n=9), adverse outcomes/complications resulting from COVID-19 (n=8), age relationship and greater severity of COVID-19 (n=8), variables related to death by COVID-19 (n=8), and diagnostic findings (n=8). Conclusion: the findings reinforce older adults’ greater vulnerability to the worsening of COVID-19, as well as to complications resulting from the disease, including the greater occurrence of death. Descriptors: Aged; Coronavirus; Severe Acute Respiratory Syndrome; Coronavirus Infections; Geriatric Nursing.


INTRODUCTION
COVID-19 is an acute respiratory disease caused by the new coronavirus (SARS-CoV-2) (1) , which was declared a Public Health Emergency of International Concern and characterized as a pandemic on March 11, 2020 (2) . The clinical picture of COVID-19, in most cases, has been reported as similar to other respiratory infections, with fever (≥37.8ºC), coryza, cough, usually dry and tired (3) . The reverse-transcriptase polymerase chain reaction (RT-PCR, polymerase chain reaction with reverse transcription) by nasopharyngeal swab was the reference standard for definitive diagnosis of infection with the new coronavirus (3) . However, it is estimated that 5% of those infected develop the most severe form of the disease, with symptoms of dyspnea and/or signs of pulmonary bleeding, severe lymphopenia, and kidney failure (3) .
Due to the physiological changes that occur with the human aging process and compromise the immune system, and the greater number of complications resulting from chronic diseases, older adults have been the most vulnerable to severe forms of COVID-19 and for evolution to death (4) . In an epidemiological cohort study conducted in China, most cases of COVID-19 and the worst prognosis for this disease were among older adults (5) . Supporting these findings, data demonstrated that the occurrence of death by COVID-19 increased exponentially from 3 to 5% among people aged 65├75 years, from 4 to 11% among people aged 75├85 years and from 10 to 27% among people aged 85 years and over. Moreover, people aged 65 and over represented 45% more hospital admissions, 53% of occupations in Intensive Care Units and 80% of deaths (6) . This leads to the belief that more comprehensive measures are needed to protect older adults.
In this regard, studies are needed to subsidize the care of health professionals to older adults with COVID-19 and, likewise, to give direction to sectoral and intersectoral actions under an integrating look among all instances involved in facing this pandemic situation. This scientific basis can support health teams' work, in order to develop interventions that can favor older adults' management and health care.
Given the above, the scoping review is considered a useful tool to identify and synthesize scientific knowledge (7) , especially in the COVID-19 pandemic, enabling planning care actions for older adults, which are foundations in evidence-based practice. Furthermore, assessment of studies may target priority areas that need to advance knowledge on this emerging topic.

OBJECTIVE
To map the scientific knowledge about COVID-19 in older adults.

METHODS
This is scoping review literature developed according to the Joanna Briggs Institute protocol (7) .
To develop the research question, Population, Concept and Context (PCC) (7) was used, being: P -older adults; C -COVID-19; C -scientific knowledge. Thus, the guiding question was established: what scientific knowledge is available in the world about COVID-19 in older adults? Older adults were defined as persons aged 60 and over (8) ; COVID-19 was considered to be the disease caused by the new coronavirus (2019 novel coronavirus, acronym 2019-nCoV) (1) .
As an eligibility criterion, original articles, case reports and case series were all considered, all about COVID-19 and with data referring to older adults, from December 2019, when the first study on said disease (1) . Letters to the editor, opinion articles, and reflection articles were excluded.

Search strategy
In the first stage, a search was carried out in the National Library of Medicine National Institutes of Health (PubMed), Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases, in which titles, abstracts and descriptors found were analyzed. In the second stage, all keywords and descriptors were used to identify the articles in other databases: Web of Science and Latin American and Caribbean Literature in Health Sciences (LILACS). In the third stage, the studies published on the PubCovid-19 platform (http://pubcovid19.pt/index.php), which covers articles published on COVID-19, divided into several themes, were analyzed as an additional source. Studies on the theme "older adults" were considered.
Search for primary studies was carried out on April 17, 2020. To that end, controlled and uncontrolled descriptors were delimited according to the databases using advanced search tools, i.e., the selected descriptors were crossed and combined using the Boolean operators "AND" and "OR". The controlled descriptors (MESH) adopted in search strategy for primary studies were "Coronavirus, Coronavirus Infections", "Severe Acute Respiratory Syndrome", "SARS Virus" and "aged", "aged, 80 and over".
Considering that there are no specific descriptors available for the new coronavirus and that the first case of the disease was reported in December 2019 (1) , the time frame was used to search the databases for primary studies (December 2019 until the data collection time).

Study selection and data extraction
The articles found were imported into the program on the Web Endnote -Clarivate Analytics (https://access.clarivate.com/ login?app=endnote) for identification and exclusion of duplicates. Subsequently, the Rayyan QCRI -Qatar Computing Research Institute (https://rayyan.qcri.org/welcome) program was used to manage the selection process of the final sample.
For data extraction, a script was elaborated containing information related to authorship, year and place of publication, type of study, participants, study period, and results. Article assessment and data extraction were conducted by two independent reviewers (NGNO and MADR), with disagreements sorted out by a third reviewer (AFB).

Analysis of evidence
Data synthesis was performed descriptively considering the construction of thematic categories, which addressed the results of original studies on COVID-19 in older adults worldwide.

RESULTS
The Preferred Reporting Items for Systematic Review and Meta-Analys for Scoping Reviews (PRISMA) diagram (9) was used to present the article selection steps (Figure 1).
In the first stage, 440 articles were found in the databases and 79 identified in the PubCovid-19 Platform, 103 of which were excluded by duplicate. After reading all titles and abstracts, 92 articles were included for reading in full, in order to answer the research question. Studies that did not meet the inclusion criteria (n=61) were excluded due to different population (n=19), study design (n=37), and others (n=5). Therefore, 31 articles made up the final sample of this scoping review ( Figure 1).
Of the 31 articles analyzed, all were published in 2020 and the majority in China (n=23). Case report (n=13) and retrospective (n=13) studies figured prominently, which aimed mainly to investigate the epidemiological, clinical and diagnostic characteristics of COVID-19.
With regard to case studies/case series (n=13), a large part (n=6) occurred in January 2020 aiming to report, by and large, the clinical characteristics, the diagnostic findings and the prospects for treatment of the first confirmed cases for COVID-19. Other information was highlighted in these reports, such as: improvement of serial laboratory parameters and oxygenation with the infusion of plasma in treatment of two older adults hospitalized with COVID-19 (10) ; the best clinical evolution of a female older adult immunocompromised in relation to her immunocompetent spouse (11) ; syncope (12) , malnutrition (13) and rhabdomyolysis (14) in cases of older adults with COVID-19; and diagnostic findings by computed tomography (15)(16)(17)  -When receiving lopinavir/ritonavir and hydroxychloroquine, older adults maintained persistent fever, hypoxemia, and progressive bilateral infiltrations.
-After plasma infusion, patients showed improvement in oxygenation and chest X-ray, and a decrease in inflammatory markers and viral loads.
-After application of methylprednisolone, before plasma infusion, there was a rapid improvement in serial laboratory and oxygenation standards.
Valentina S, Alessio P, Hans-Ulrich I, 2020 (Italy) (11) Case studies -02 patients with COVID-19 (couple), the woman being treated with chemotherapy for recurrent breast cancer, and her husband considered healthy (controlled hypertension). Both 60 years old.
-Both patients were treated with darunavir/cobicistat and hydroxychloroquine.
-The immunocompromised woman evolved, without the need for intensive care and was discharged after 6 days.
-The husband needed intensive care and his recovery was slow, although he was also discharged from the hospital.  Figure 1 -Flow diagram of study selection in the databases according to Preferred Reporting Items for Systematic Review and Meta-Analyzes for Scoping Reviews (PRISMA) (9) of Scientific knowledge about infections by the new coronavirus in older adults: a scoping review Tavares DMS, Oliveira NGN, Rezende MAD, Bitencourt GR, Silva MB, Bolina AF.
Author, year, and country
-Patient with hypertension, chronic kidney disease, heart failure with reduced ejection fraction, benign prostatic hypertrophy, bilateral knee osteoarthritis, and mild cognitive impairment.
-Entered the emergency room with symptoms of rhabdomyolysis, including muscle pain and weakness.
-In the initial assessment, she had low fever, tachypnea, and 94% oxygen saturation.
-The COVID-19 polymerase chain reaction test of the nasopharyngeal swab was positive.
-Chest CT scan without contrast showed multiple, bilateral, irregular ground-glass opacities with a paving pattern. Using an antiviral (Abidore) did not help to reduce the patient's temperature, nor to improve her breathing pattern.
-After four days, chest computed tomography was repeated, and demonstrated increased multiple consolidation, ground-glass nodules and ground-glass nodules adjacent to the pleura.
-The patient received intravenous administration of methylprednisolone (40 mg qd), oral administration of γ-immunoglobulin and traditional Chinese medicine and noninvasive positive pressure ventilation. The dynamic computed tomography showed irregular consolidation and partially absorbed nodules, indicating that the symptoms were alleviated.
-On chest radiography, he presented ill-defined pulmonary opacities, notably on the periphery of the left lung.
-On chest computed tomography, he presented ground-glass opacities, predominantly peripheral, involving all pulmonary lobes.
Quin C et al., 2020 (China) (17) Case series -04 patients with COVID-19, 01 older adult (woman and 61 years old) -Period: January 13 th to 20 th , 2020 -The older adult patient had back pain and a dry cough, mild leukopenia, peripheral ground-glass opacities, and pulmonary consolidations in more than two pulmonary lobes.
-The older adult patient presented rapid evolution to multiple organ failure and high and persistent viral load in the lower and upper respiratory tract.
-The older adult patient died 24 days after the disease; and everyone else recovered and was discharged.
-Genomes of the cases are identical. These genomes have no direct link to the Huanan Seafood Market, but their genomes are identical to four Wuhan strings, collected on December 30, 2019, indicating a potentially wider distribution in the city.
-Signs and symptoms in older adult patients: fever and cough. The woman also had vertigo and constipation.
-On tomography, the man presented unilateral pneumonia, and the older adult, bilateral.
-Both older adults received oxygen therapy, treatment with antibiotics and antivirals with lopinavir/ritonavir (Kaletra ® ), arbidol and Shufeng Jiedu Capsule. The woman was on mechanical ventilation.
-The man improved the symptoms associated with pneumonia, and the first test was negative.
-At the end of data collection, the woman showed signs of improvement in pneumonia.
-Hypertensive and diabetic older adults were diagnosed with severe COVID-19 pneumonia associated with Severe Acute Respiratory Syndrome and septic shock.
-In the physical exam he did not present fever; however, even though using non-invasive oxygen therapy, oxygen saturation was 91%.
-The three-dimensional reconstruction of bilateral lung injuries provided a fundamental clue for early identification of COVID-19.
-Older adults showed more systemic symptoms (fever ≥38.2ºC), extensive ground-glass radiological changes, lymphopenia, thrombocytopenia and increased levels of C-reactive protein and lactic dehydrogenase.

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of Scientific knowledge about infections by the new coronavirus in older adults: a scoping review Tavares DMS, Oliveira NGN, Rezende MAD, Bitencourt GR, Silva MB, Bolina AF.
As for other designs of the studies (n=18) (Chart 2), it was found that two were carried out only with older adults, in the others (n=16), participants were constituted by the general population, which presented results on COVID-19 stratified according to age group, which included older adults. The number of study participants ranged from 17 (1) to 13,909 (23) older adults, with heterogeneous selection criteria, being: confirmed diagnoses of COVID-19 (6.24-31) ; pneumonia by COVID-19 (1.31-33) ; adults with one or more morbidities (34) ; deaths associated with COVID-19 (23.35) ; suspected cases (32) and confirmed symptomatic of the disease (36) . The sample data, from most surveys, were related to the period of January and/or February (n=13). The consecutive and nonprobabilistic sample was used in 17 studies (Chart 2).
Based on the findings of the studies included in this scoping review (n=31), six thematic categories of the main results of studies on COVID-19 in older adults were listed, as shown in Chart 3.  (27) Retrospective study -203 patients with COVID-19, 55 older adults (≥ 65 years).
-Among patients aged 65 and over, the mortality rate was 34.5%, significantly higher than that of older adults ≤ 65 years of age (4.7%) (p <0.001).
-Older adults aged 65 and over had higher initial comorbidities (p <0.001), more severe symptoms (p <0.001) and more likely to multiple organ failure (p <0.001), compared to younger patients.
-Among the older adults, a greater proportion of the severe condition of the disease was evidenced in relation to the mild one (p <0.001).
-In an multivariate analysis, the age group of 65 years and over was an independent risk factor for COVID-19 (OR=81.2; CI=1.10-5988.12).
-Differences between clinical manifestations (fever and sputum) in infected patients of different age groups were not statistically significant (p> 0.05), nor was there a statistically significant difference in the interval between the first onset of symptoms and high-resolution computed tomography (p=0.921).
-A greater number of cases of bilateral pulmonary involvement was found in patients ≥ 60 years old in relation to the others (p <0.05).
-The number of lung lesions observed by high-resolution computed tomography in patients aged 60 years or older was higher compared to those younger than 18 years old (p=0.019).
-Involvement of peripheral lung injuries in the older adult group was greater than the group of children under 18 years old (p=0.005).
-Patients were classified as non-critical (mild, common) and critical (severe; critical). Critical patients were older (p=0.003) and had more underlying disease than non-critical patients (p=0.009).
-Characteristics of the cases in three periods: the first period was for patients with disease onset before January 1 st , the date on which the Huanan Wholesale Seafood Market was closed (older adults -65 years and over -represented 23%); the second period was for those beginning between 1 and 11 January, which was the date on which the RT-PCR reagents were supplied to Wuhan (older adults -65 years or older -represented 42%); and the third period were those with onset of the disease on or after January 12 (older adults -65 years or older -represented 37%).
-It was noted that few of the first cases occurred in children, and almost half of the 425 cases were in adults aged 60 years and over. Chen N et al., 2020 (China) (33) Retrospective study -99 patients with 2019-nCoV pneumonia, 37 older adults (≥ 60 years old).
-11.0% died, seven of whom were 60 years old and over.
-The first two deaths were male, had no chronic diseases and were 61 (patient 1) and 69 years old (patient 2). Both patients had severe pneumonia and severe acute respiratory syndrome after hospitalization, being transferred to the Intensive Care Unit, where they received respiratory therapy assisted by an intubated ventilator. The intervals between the onset of symptoms and the use of ventilator-assisted breathing in the two patients were 3 and 10 days, respectively. The course of the disease and lung injuries progressed rapidly in both cases and both developed multiple organ failure in a short time.

Author, year, and country Type of study Study participants/Period Main results
Wolf MS et al., 2020 (United States) (34) Cross-sectional study -630 adults with one or more comorbidities, being 153 older adults (≥ 65 years old).
-The threat of a COVID-19 outbreak was rated as most serious by older adults aged 70 and over.
-Older adults showed less knowledge about the prevention and symptoms of COVID-19 compared to young people, but no significant difference was identified.
-The mean age for the SpO 2 ≥90% group was 37.0 years, while for SpO 2 <90%, it was 70.5 years.
-All deaths occurred in the SpO 2 <90% group formed by older patients, with more comorbidities and higher plasma levels of IL6, IL10, lactate dehydrogenase and C-reactive protein.
The diagnostic findings by computed tomography (n=8) identified changes in the lungs, in particular, the involvement of the pulmonary lobes (32,36) . They also found a lower proportion of lymphocytes in older adults compared to young people (32) and the occurrence of lymphocytopenia (26) (Chart 3).

DISCUSSION
The current study is one of the first to map scientific knowledge about infection with the new coronavirus in older adults. Mapping the literature, which deals with aspects related to COVID-19 in this population, allowed to outline the different contexts of investigations with this theme, with regard to adverse outcomes/complications, the relationship of age and greater severity of the disease, deaths, clinical signs, diagnostic findings, and other information.
Most of studies in this review concentrated in China, because the outbreak started in this country (1) , and presented a descriptive design, with non-probabilistic and consecutive samples. The option for the design, possibly, was due to the emergency nature of building knowledge about the COVID-19 pandemic. However, the set of findings shows that there are still few studies in the world, which were carried out specifically with older adults, highlighting the need to expand scientific knowledge on this topic. Thus, it is necessary to increasingly qualify scientific productions according to the evolution of the pandemic and, therefore, to advance in knowledge about the dynamics of the disease and its impact on society, on older adults, and their families.
The greater likelihood that older adults will develop complications from infection with the new coronavirus compared to the general population was identified in this review. The analysis of information on adverse outcomes related to COVID-19 in older adults, such as progression of disease severity and hospital discharge, can provide information to guide the most effective treatment of the disease (39) in managing care and health service resources.
It also favors organization of work in primary care, which, in addition to maintaining continuity of care for chronic diseases, should also undertake health surveillance actions. In this perspective, nurses, based on the situational health diagnosis, will be able to identify the most vulnerable older adults and promote health education. The approach to older adults' social support network provides the capillarity of effective information on preventive measures and care related to COVID-19, postponing its adverse effects.

Thematic categories (number of articles) Results of studies
Other information (n=9) High costs related to deaths due to COVID-19 (35) High prevalence of comorbidities in older adults and/or a higher proportion in relation to young people (24)(25)27) ; Common comorbidities: hypertension, diabetes mellitus and cardiovascular diseases (26) ; Higher occurrence of infection by the new coronavirus in older adults (37) ; Treatment of COVID-19 with plasma infusion (10) ; Clinical evolution of COVID-19 in an immunodepressed patient (11) ; Genomic characteristics (19) .
of Scientific knowledge about infections by the new coronavirus in older adults: a scoping review Tavares DMS, Oliveira NGN, Rezende MAD, Bitencourt GR, Silva MB, Bolina AF. development of serious charts (5,25,28,32) are responsible for the high death rate by COVID-19 in older adults. This relationship may be linked to physiological changes in the immune system resulting from the aging process as well as the greater number and complications of chronic diseases in older adults (4) . The variables related to higher probability of death in older adults, verified in this review, contribute to outline the characteristics of older adults who are at higher risk for this outcome. Therefore, attention is needed to the particularities of the development of the clinical picture in older adults. Dyspnea (24,(26)(27) , fever (12,20,(22)(23)(24)(26)(27) , cough (19)(20)(26)(27) , fatigue (28) , and lower oxygen saturation rates (<90%) (21,38) are the main clinical findings that can guide the diagnosis of COVID -19. In a cohort study, older adults with mild and/or moderate infection with the new coronavirus were found to have fever as the most frequent symptom (82-87%), followed by coughing (36-66%) (40) . It should be noted that fever may not be present in older adults, referring to the need to investigate other symptoms, such as tiredness and cough (40) . Additionally, most of these studies reported the signs and symptoms of COVID-19 in patients with infection diagnosed in hospitals (21,26,38,40) , which assumes the relevance of advancing knowledge about the dynamics of the disease in older adults in representative population samples and before arriving at the hospital, seeking to prevent hospitalizations and worsening cases.
Considering the severity of the disease and its worst prognosis, the need to disseminate preventive measures for COVID-19 is reinforced in all areas of care, aiming at promoting older adults' rights to life and health. In this regard, COVID-19 prevention among older adults with advanced age should be preferred, requiring interventions that can contain the worsening of the disease, in positive cases, minimizing the occurrence of these outcomes. Teams experienced in geriatrics and gerontology need to be agile in making the most appropriate decision in the context of older adults with advanced age.
Regarding diagnostic findings, computed tomography scans showed greater involvement of the pulmonary lobes (36)(37) and proportion of subpleural line and pleural thickening (36) ; in relation to young people, lower proportion of lymphocytes (32) and lymphocytopenia (26) . These radiological changes may be absent at the beginning of the disease and be minimal in the mild form (25) . Therefore, other findings can be considered in the clinical assessment of older adults, such as the lowest proportion of lymphocytes (32) and lymphocytopenia (26) , as verified in this scoping review.
Thus, clinical signs and imaging tests can guide the diagnosis of COVID-19 and provide early isolation and treatment for older adults. However, no studies were found that offered specific information about the treatment of this disease, showing the relevance of investments in research.
Considering the higher risk of complications and death by COVID-19 among older adults, its protection has been considered a priority action in Brazil (41) . In this perspective, in addition to individual clinical focus, it is necessary, in this phase of the pandemic, to advance in reflections and research on the broad geriatric and gerontological approach in caring for older adults, namely: what are the impacts of social isolation for older adults? How to deal with the various situations that disadvantage social mitigation measures in older adults, such as those who live in a context of high social vulnerability and live alone? What is the relationship between frailty and geriatric syndromes with the occurrence of COVID-19?
Such reflections and investigations are urgent, as they may support health professionals' role in caring for older adults and their families before this pandemic context. Experts from the American Society of Geriatrics stressed the importance of expanding knowledge in gerontology and geriatrics to health professionals to understand the health peculiarities of older adults and their impact on coping with COVID-19 (42) . The Brazilian Society of Geriatrics and Gerontology (SBGG -Sociedade Brasileira de Geriatria e Gerontologia), aware of the severity of the disease in older adults with comorbidities, recommends the adoption of measures to restrict social contact, avoiding crowds or trips during the COVID-19 pandemic. Moreover, it encourages that older adults should preferably be cared for at home, avoiding collective exposure in health services and that, in the event of being assisted by caregivers or health professionals, they should be screened for flu-like syndromes. Furthermore, special attention should be given to older adults who live in nursing homes (NHs), as they tend to be more frail (43) .
In particular, nursing has a decisive role in facing the pandemic of COVID-19, considering that it corresponds to the largest health workforce and, in Brazil, they operate in all health care networks (44) .

Study limitations
The types of studies available in scientific literature, at the beginning of the pandemic, were mostly descriptive and few carried out experimental investigations, testing the main interventions. On the other hand, the studies included in this review were not analyzed for methodological limitations or risk of bias, as proposed for scoping review. These two aspects may have brought together investigations with a low level of evidence; however, they met the proposed objective of presenting an overview of scientific knowledge available worldwide about COVID-19 in older adults.

Contributions to nursing
In this scoping review, no studies were identified that addressed nursing care directed to older adults affected with COVID-19. It is worth mentioning that the year 2020 was chosen to honor the bicentenary of Florence Nightingale, a precursor to modern nursing. Florence worked in the Crimean War (45) and, from her legacy, nurses have played an essential role in the prevention and control of infections, as well as in social mitigation measures (46) . Such theoretical bases need to be rescued to support nursing professionals' work in coping with COVID-19. The pandemic moment of COVID-19 reinforces the need for nurses to provide qualified and safe gerontological care, through fundamental professional training, and it is essential to develop care actions for older adults, considering, both in present and future scenarios, the particularities and specificities of this population.

CONCLUSION
Most of the research was carried out in China with a retrospective and case study type or case series design. With regard to case reports or case series, most aimed to report the clinical of Scientific knowledge about infections by the new coronavirus in older adults: a scoping review Tavares DMS, Oliveira NGN, Rezende MAD, Bitencourt GR, Silva MB, Bolina AF. characteristics, diagnostic findings and treatment perspectives of the first confirmed cases of the disease. As for the other studies, participants ranged from 17 to 13,909 older adults, with heterogeneous selection criteria. Six thematic categories were identified: adverse outcomes/complications resulting from COVID-19, age relationship and greater severity of COVID-19, variables related to death by COVID-19, clinical signs and symptoms, diagnostic findings, and other information.
In general, scientific knowledge about COVID-19 in older adults is still incipient. However, they already indicate high vulnerability of older adults to the worsening of COVID-19 and to complications resulting from the disease, which includes a higher proportion of hospitalizations in Intensive Care Units and severe pneumonia and a lower proportion of hospital discharge compared to younger people. They also demonstrate that advanced age was related to the occurrence of death. There was also a major episode of CO-VID-19 infection in older adults, high cost due to deaths from the disease and high occurrence of comorbidities in this population group, when infected. In this context, it is suggested to carry out national surveys with representative samples of older adults in different Brazilian states, in order to contribute to improving health care for older adults before the COVID-19 pandemic.