Clinical courses and outcomes of hospitalized adult patients with seasonal influenza in Korea, 2011-2012: Hospital-based Influenza Morbidity & Mortality (HIMM) surveillance

Cost-Effectiveness of Influenza Vaccination Strategies in Adults: Older Adults Aged ≥65 Years, Adults Aged 50–64 Years, and At-Risk Adults Aged 19–64 Years

The high disease burden of influenza in elderly and chronically ill adults may be due to the suboptimal effectiveness and mismatch of the conventional trivalent influenza vaccine (TIV). This study evaluated the cost-effectiveness of quadrivalent (QIV), adjuvanted trivalent (ATIV), and high-dose quadrivalent (HD-QIV) vaccines versus TIV used under the current Korean National Immunization Program (NIP) in older adults aged ≥65 years. We also evaluated the cost-effectiveness of programs for at-risk adults aged 19–64 and adults aged 50–64. A one-year static population model was used to compare the costs and outcomes of alternative vaccination programs in each targeted group. Influenza-related parameters were derived from the National Health Insurance System claims database; other inputs were extracted from the published literature. Incremental cost-effectiveness ratios (ICERs) were assessed from a societal perspective. In the base case analysis (older adults aged ≥65 years), HD-QIV was superior, with the lowest cost and highest utility. Compared with TIV, ATIV was cost-effective (ICER $34,314/quality-adjusted life-year [QALY]), and QIV was not cost-effective (ICER $46,486/QALY). The cost-effectiveness of HD-QIV was robust for all parameters except for vaccine cost. The introduction of the influenza NIP was cost-effective or even cost-saving for the remaining targeted gr3oups, regardless of TIV or QIV.

Euglycemic diabetic ketoacidosis in a patient with type 1 diabetes and SARS-CoV-2 pneumonia: case-report and review of the literature

OBJECTIVE

Recent publications on Coronavirus Disease-2019 (COVID-19) report that diabetic people with or without co-morbidities are at higher risk of developing severe and/or fatal illnesses.

METHOD AND RESULT

We report the first case of a 60-year-old man with a 27-year history of type 1 diabetes mellitus, infected by SARS-CoV-2 presenting with an euglycaemic ketoacidosis and an acute respiratory distress syndrome.

CONCLUSION

This case report reminds us of the importance of adjusting more recent glucose-lowering drugs, including sodium-glucose cotransporter 2 inhibitors, in the overall management of type 1 diabetic individuals during the ongoing COVID-19 outbreak.

ABBREVIATIONS

COVID-19: Coronavirus disease 2019 (SARS-CoV-2) virus, T1DM: Type 1 diabetes mellitus, T2DM: Type 2 diabetes mellitus, SGLT2i: Sodium-glucose cotransporter 2 inhibitor, DKA: diabetic ketoacidosis, euDKA: euglycaemic diabetic ketoacidosis.

Comparison of Comorbidities in Relation to Critical Conditions among Coronavirus Disease 2019 Patients: A Network Meta-Analysis

Severe illness and poor outcome are mainly associated with aging or certain medical comorbidities, especially chronic diseases. However, factors for unfavorable prognosis have not been well described owing to relatively small sample sizes and single-center reports. Therefore, this study aimed to compare the contribution of comorbidities in the development of critical conditions in coronavirus disease 2019 (COVID-19) patients. Pooled estimates of relative risks (RRs) and their 95% confidence intervals (CIs) were calculated by conducting a meta-analysis and network meta-analysis of 18 studies. Chronic obstructive pulmonary disease (COPD) was most strongly associated with the overall critical condition (RR = 4.22, 95% CI = 3.12 - 5.69), followed by cardiovascular disease (CVD) (RR = 3.00, 95% CI = 2.41 - 3.73), malignancy (RR = 2.91, 95% CI = 2.16 - 3.91), cerebrovascular accident (CVA) (RR = 2.86, 95% CI = 1.95 - 4.19), diabetes (RR = 2.10, 95% CI = 2.16 - 3.91), hypertension (RR = 2.02, 95% CI = 1.82 - 2.23), and chronic kidney disease (RR = 2.00, 95% CI = 1.36 - 2.94). The presence of comorbidities except for chronic liver disease and chronic kidney disease significantly increased the risk of severe infection, intensive care unit (ICU) admission, and cardiac injury in the subgroup analysis by types of critical conditions. Preexisting hypertension and diabetes additionally increased the risk of acute respiratory distress syndrome (ARDS). Among comorbidities, COPD had the highest probability of leading to severe COVID-19, ICU admission, and liver injury, while malignancy was most likely to cause ARDS and cardiac injury. In summary, preexisting COPD, CVD, CVA, hypertension, diabetes, and malignancy are more likely to worsen the progression of COVID-19, with severe infection, ICU admission requirement, and cardiac injury development.

Predictors of severity and in-hospital mortality in patients with influenza

Influenza virus is a common agent of acute respiratoty infections during epidemic periods. It is a major cause of morbidity and mortality and represent a significant burden on the healthcare system. We aimed to evaluate predictors of severity and of in-hospital mortality in patients hospitalized with influenza infection. We performed a retrospective cohort study of hospitalized, laboratory confirmed cases of influenza disease in Centro Hospitalar de São João between October 2016-May 2017 and October 2017-May 2018. The endpoints being analysed were severity and in-hospital mortality. A multivariate logistic regression analysis was used to determine independent predictors of severity and of in-hospital mortality. We studied 221 hospitalized influenza infection cases. Mean age 66±16 years, 57.9% were male, thirty-seven patients (16.7%) died in-hospital and 101 patients (45.7%) met severity criteria. C-reactive protein (CRP) was the only independent predictor of severity as well as the only independent predictor of higher in-hospital mortality in patients admitted due to influenza infection. Multivariate-adjusted CRP OR for severity was 1.10, 95% CI 1.06-1.15 per each 10 mg/L increase in CPR and for in-hospital mortality risk the OR was of 1.05, 95% CI 1.01-1.09, p=0.01, per each 10 mg/L increase. Concluding, in patients' hospital-admitted due to influenza infection CRP was the only predictor of severity with a 10% increased risk of inotropic support/ventilatory support/prolonged hospitalization needs and a 5% increase risk of in-hospital death per each 10 mg/l increase.

Hospital utilization rates for influenza and RSV: a novel approach and critical assessment

BACKGROUND

Influenza and respiratory syncytial virus (RSV) contribute significantly to the burden of acute lower respiratory infection (ALRI) inpatient care, but heterogeneous coding practices and availability of inpatient data make it difficult to estimate global hospital utilization for either disease based on coded diagnoses alone.

METHODS

This study estimates rates of influenza and RSV hospitalization by calculating the proportion of ALRI due to influenza and RSV and applying this proportion to inpatient admissions with ALRI coded as primary diagnosis. Proportions of ALRI attributed to influenza and RSV were extracted from a meta-analysis of 360 total sources describing inpatient hospital admissions which were input to a Bayesian mixed effects model over age with random effects over location. Results of this model were applied to inpatient admission datasets for 44 countries to produce rates of hospital utilization for influenza and RSV respectively, and rates were compared to raw coded admissions for each disease.

RESULTS

For most age groups, these methods estimated a higher national admission rate than the rate of directly coded influenza or RSV admissions in the same inpatient sources. In many inpatient sources, International Classification of Disease (ICD) coding detail was insufficient to estimate RSV burden directly. The influenza inpatient burden estimates in older adults appear to be substantially underestimated using this method on primary diagnoses alone. Application of the mixed effects model reduced heterogeneity between countries in influenza and RSV which was biased by coding practices and between-country variation.

CONCLUSIONS

This new method presents the opportunity of estimating hospital utilization rates for influenza and RSV using a wide range of clinical databases. Estimates generally seem promising for influenza and RSV associated hospitalization, but influenza estimates from primary diagnosis seem highly underestimated among older adults. Considerable heterogeneity remains between countries in ALRI coding (i.e., primary vs non-primary cause), and in the age profile of proportion positive for influenza and RSV across studies. While this analysis is interesting because of its wide data utilization and applicability in locations without laboratory-confirmed admission data, understanding the sources of variability and data quality will be essential in future applications of these methods.

A comprehensive review on clinical and mechanistic pathophysiological aspects of COVID-19 Malady: How far have we come?

Since its outbreak in 2019, the coronavirus disease (COVID-19) has become a pandemic, affecting more than 52 million people and causing more than 1 million mortalities globally till date. Current research reveals a wide array of disease manifestations and behaviors encompassing multiple organ systems in body and immense systemic inflammation, which have been summarized in this review. Data from a number of scientific reviews, research articles, case series, observational studies, and case reports were retrieved by utilizing online search engines such as Cochrane, PubMed, and Scopus from December 2019 to November 2020. The data for prevalence of signs and symptoms, underlying disease mechanisms and comorbidities were analyzed using SPSS version 25. This review will discuss a wide range of COVID-19 clinical presentations recorded till date, and the current understanding of both the underlying general as well as system specific pathophysiologic, and pathogenetic pathways. These include direct viral penetration into host cells through ACE2 receptors, induction of inflammosomes and immune response through viral proteins, and the initiation of system-wide inflammation and cytokine production. Moreover, peripheral organ damage and underlying comorbid diseases which can lead to short term and long term, reversible and irreversible damage to the body have also been studied. We concluded that underlying comorbidities and their pathological effects on the body contributed immensely and determine the resultant disease severity and mortality of the patients. Presently there is no drug approved for treatment of COVID-19, however multiple vaccines are now in use and research for more is underway.

SARS-CoV-2 infection and diabetes mellitus: A North Eastern Romanian experience

As it spread globally, the new SARS-CoV-2 virus was first confirmed in Romania in February 2020, inevitably infecting individuals with diabetes mellitus (DM) along the way. Diabetes is known to affect the response of the body to pathogens and, according to studies conducted in the last 3 months, it appears that diabetic patients are at a higher risk for developing severe forms of the disease and multiple complications. We performed a retrospective study in order to assess the patients with SARS-CoV-2 infection and DM admitted to 'Sf. Parascheva' Clinical Hospital of Infectious Diseases from March 4th until June 30th, 2020. Of the total 1,080 patients admitted during this period, 85 patients (7.87%) had underlying DM, mostly type 2 (82 cases, 96.46%); the mean age of these patients was 62, and 42 were men (49.41%). Chest CTs revealed indicative SARS-CoV-2 images for all patients and their treatment included individually tailored administration of hydroxychloroquine/lopinavir + ritonavir/enoxaparin sodium/tocilizumab/antibiotherapy according to the then national and international guidelines. In total, 70 patients (82.35%) were cured and 15 succumbed to MODS and/or associated neoplasia, bringing the fatality rate to 17.64%. Although advanced age and DM have been associated with aggravated forms of SARS-CoV-2 infection, over 80% of the patients included in the present study were cured. Nonetheless, diabetes appears to be a significant predictor of morbidity and mortality in the SARS-CoV-2 infection.

Impact of Comorbidities on Clinical Outcome of Patients with COVID-19: Evidence from a Single-center in Bangladesh

Background: COVID-19 patients with preexisting comorbidities are at increased risk of exacerbated symptoms. Objectives: The current study aimed to firstly assess the impact of predisposed comorbidities on the severity of COVID-19, and secondly investigating the associated clinical outcome of patients with COVID-19 infection in Bangladesh. Methods: In this single-center retrospective study, the medical data of 157 hospitalized COVID-19 patients, including their preexisting comorbidities, from April 30, 2020, to June 15, 2020, are analyzed. Patients’ clinical outcomes in moderate-to-critical COVID-19 infections need for Intensive Care Unit (ICU) and mechanical ventilation support, and mortality were evaluated, with emphasis on predisposed chronic diseases. Results: Approximately 40.1 and 7.6% of patients (n = 157) presented severe and critical COVID-19 symptoms, respectively (P = 0.001). The most common comorbidity was diabeties (24.8%), followed by hypertension (23.2). Patients with one or two comorbidities did not present critical symptoms. Most of the critical cases had at least five comorbidities compared to those with 3 or 4 comorbidities (33.3% versus 8.3%; P = 0.038). The highest incidence of critical COVID-19 (41.7%) was among those with 7 comorbidities. Compared to patients with 4 or fewer comorbidities, patients with 5 (n = 15), 6 (n = 4), and 7 (n = 7) comorbidities were more hospitalized at ICU (above 70%, P = 0.025) and had a higher need for intubation support (above 60%, P = 0.038), and presented higher 30-day mortality (6.7, 25, and 28.6%, respectively; P = 0.002), which can be attributed to the declined clinical outcome of patients with 5 or more comorbidities in moderate-to-critical COVID-19 infection. Conclusions: This study demonstrated a positive association between the severity of COVID-19 and the number of predisposed comorbidities, which leads to poor clinical outcomes.

COVID-19 and Comorbidities: Is Inflammation the Underlying Condition in Children? A Narrative Review

This paper examines the potential link between COVID-19 and the presence of comorbidities and assesses the role of inflammation in this correlation. In COVID-19 patients, the most frequently associated diseases share a pathogenic inflammatory basis and apparently act as a risk factor in the onset of a more severe form of the disease, particularly in adulthood. However, in children, the understanding of the underlying pathogenic mechanisms is often complicated by the milder symptoms presented. A series of theories have, therefore, been put forward with a view of providing a better understanding of the role played by inflammation in this dramatic setting. All evidence available to date on this topic is discussed in this review.

Comorbidities in Patients with COVID-19 and Their Impact on the Severity of the Disease

Infection with COVID-19 is associated with significant morbidity, especially in patients with chronic medical conditions. At least one-fifth of cases require supportive care in intensive care units, which have limited availability in most developing countries. A literature search was conducted on PubMed, Medline, Scopus, Embase, and Google Scholar to find articles published by May 7, 2020 on the role of comorbidities in patients with COVID-19 and the impact of comorbidities on the disease. This review highlighted that patients with comorbidities are more likely to experience severe disease than those with no other conditions; that is, comorbidities correlated with greater disease severity in patients with COVID-19. Proper screening of COVID-19 patients should include careful inquiries into their medical history; this will help healthcare providers identify patients who are more likely to develop serious disease or experience adverse outcomes. Better protection should also be given to patients with COVID-19 and comorbidities upon confirmation of the diagnosis. This literature review showed that the comorbidities most often associated with more severe cases of COVID-19 are hypertension, cardiovascular disease, and diabetes. Individuals with these comorbidities should adopt restrictive measures to prevent exposure to COVID-19, given their higher risk of severe disease.

Newly-diagnosed diabetes and admission hyperglycemia predict COVID-19 severity by aggravating respiratory deterioration

AIMS

We investigated whether pre-existing diabetes, newly-diagnosed diabetes, and admission hyperglycemia were associated with COVID-19 severity independently from confounders.

METHODS

We retrospectively analyzed data on patients with COVID-19 hospitalized between February and April 2020 in an outbreak hospital in North-East Italy. Pre-existing diabetes was defined by self-reported history, electronic medical records, or ongoing medications. Newly-diagnosed diabetes was defined by HbA1c and fasting glucose. The primary outcome was a composite of ICU admission or death.

RESULTS

413 subjects were included, 107 of whom (25.6%) had diabetes, including 21 newly-diagnosed. Patients with diabetes were older and had greater comorbidity burden. The primary outcome occurred in 37.4% of patients with diabetes compared to 20.3% in those without (RR 1.85; 95%C.I. 1.33-2.57; p < 0.001). The association was stronger for newly-diagnosed compared to pre-existing diabetes (RR 3.06 vs 1.55; p = 0.004). Higher glucose level at admission was associated with COVID-19 severity, with a stronger association among patients without as compared to those with pre-existing diabetes (interaction p < 0.001). Admission glucose was correlated with most clinical severity indexes and its association with adverse outcome was mostly mediated by a worse respiratory function.

CONCLUSION

Newly-diagnosed diabetes and admission hyperglycemia are powerful predictors of COVID-19 severity due to rapid respiratory deterioration.

Prevalence of comorbidities and its effects in patients infected with SARS-CoV-2: a systematic review and meta-analysis

BACKGROUND

An outbreak of coronavirus disease 2019 (COVID-19) occurred in Wuhan, China; the epidemic is more widespread than initially estimated, with cases now confirmed in multiple countries.

AIMS

The aim of this meta-analysis was to assess the prevalence of comorbidities in the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infected patients and the risk of underlying diseases in severe patients compared to non-severe patients.

METHODS

A literature search was conducted using the databases PubMed, EMBASE, and Web of Science through February 25, 2020. Odds ratios (ORs) and 95% confidence intervals (CIs) were pooled using random-effects models.

RESULTS

Seven studies were included in the meta-analysis, including 1 576 infected patients. The results showed the most prevalent clinical symptom was fever (91.3%, 95% CI: 86-97%), followed by cough (67.7%, 95% CI: 59-76%), fatigue (51.0%, 95% CI: 34-68%) and dyspnea (30.4%, 95% CI: 21-40%). The most prevalent comorbidities were hypertension (21.1%, 95% CI: 13.0-27.2%) and diabetes (9.7%, 95% CI: 7.2-12.2%), followed by cardiovascular disease (8.4%, 95% CI: 3.8-13.8%) and respiratory system disease (1.5%, 95% CI: 0.9-2.1%). When compared between severe and non-severe patients, the pooled OR of hypertension, respiratory system disease, and cardiovascular disease were 2.36 (95% CI: 1.46-3.83), 2.46 (95% CI: 1.76-3.44) and 3.42 (95% CI: 1.88-6.22) respectively.

CONCLUSION

We assessed the prevalence of comorbidities in the COVID-19 patients and found that underlying disease, including hypertension, respiratory system disease and cardiovascular disease, may be risk factors for severe patients compared with non-severe patients.

Vaccination coverage with the pneumococcal and influenza vaccine among persons with chronic diseases in Shanghai, China, 2017

BACKGROUND

Adults with chronic conditions such as heart disease, diabetes, or lung disease are more likely to develop complications from a number of vaccine-preventable diseases, including influenza and pneumonia. In this study, we use the data from a chronic disease management information system in Shanghai to estimate vaccination coverage and characterize predictors of seasonal influenza and 23-valent pneumococcal polysaccharide vaccine (PPSV23) vaccination among people with chronic disease in Shanghai.

METHODS

The Shanghai Centers for Disease Control and Prevention have information systems related to chronic disease management, hospital records, and immunizations. Data from individuals with hypertension, diabetes and chronic obstructive pulmonary disease (COPD) were abstracted during July 2017. The main outcome was coverage of pneumococcal and influenza vaccination. Vaccination coverage was calculated across demographic groups. Significance in bivariate associations was assessed through Pearson's chi-square tests, and in multivariable models through logistic regression models with a forward stepwise method to select variables.

RESULTS

In the sample of 2,531,227 individuals ≥15 years, 22.8% were vaccinated for pneumonia from January 2013 to July 2017, and the vaccination coverage of influenza in the 2016/17 influenza season was 0.4%. Vaccination coverage was highest in those 70-79 and lowest in those younger than 60. Compared to urban areas, uptake in rural areas was higher for pneumonia vaccination (OR: 2.43, 95% CI: 2.41, 2.45), but lower for influenza vaccination (OR: 0.55, 95% CI: 0.51, 0.59). Having a greater number of chronic diseases was associated with higher likelihood of pneumonia vaccination (3 vs 1: OR: 1.68, 95% CI: 1.64, 1.71), but this relationship was not statistically significant for influenza vaccination.

CONCLUSIONS

We found low levels with of pneumococcal vaccination, and extremely low uptake of influenza vaccination among individuals with high risk conditions in Shanghai who should be priority groups targeted for vaccination. Interventions could be designed to target groups with low uptake - like younger adults, and individuals who have not yet retired.

Prevalence of comorbidities and its effects in patients infected with SARS-CoV-2: a systematic review and meta-analysis

BACKGROUND

An outbreak of coronavirus disease 2019 (COVID-19) occurred in Wuhan, China; the epidemic is more widespread than initially estimated, with cases now confirmed in multiple countries.

AIMS

The aim of this meta-analysis was to assess the prevalence of comorbidities in the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infected patients and the risk of underlying diseases in severe patients compared to non-severe patients.

METHODS

A literature search was conducted using the databases PubMed, EMBASE, and Web of Science through February 25, 2020. Odds ratios (ORs) and 95% confidence intervals (CIs) were pooled using random-effects models.

RESULTS

Seven studies were included in the meta-analysis, including 1 576 infected patients. The results showed the most prevalent clinical symptom was fever (91.3%, 95% CI: 86-97%), followed by cough (67.7%, 95% CI: 59-76%), fatigue (51.0%, 95% CI: 34-68%) and dyspnea (30.4%, 95% CI: 21-40%). The most prevalent comorbidities were hypertension (21.1%, 95% CI: 13.0-27.2%) and diabetes (9.7%, 95% CI: 7.2-12.2%), followed by cardiovascular disease (8.4%, 95% CI: 3.8-13.8%) and respiratory system disease (1.5%, 95% CI: 0.9-2.1%). When compared between severe and non-severe patients, the pooled OR of hypertension, respiratory system disease, and cardiovascular disease were 2.36 (95% CI: 1.46-3.83), 2.46 (95% CI: 1.76-3.44) and 3.42 (95% CI: 1.88-6.22) respectively.

CONCLUSION

We assessed the prevalence of comorbidities in the COVID-19 patients and found that underlying disease, including hypertension, respiratory system disease and cardiovascular disease, may be risk factors for severe patients compared with non-severe patients.

Demographic, clinical, and virological characteristics of patients with a laboratory-confirmed diagnosis of influenza during three consecutive seasons, 2015/2016-2017/18, in the Islamic Republic of Iran

BACKGROUND

There are minimal data on the differences in demographics, clinical presentations and outcomes for patients with different types and sub-types of influenza in the Middle East.

OBJECTIVES

To use population-based data from Iran to investigate factors associated with unfavorable disease outcome.

STUDY DESIGN

Clinical data were compiled from the Iranian Ministry of Health for patients of all ages who fulfilled the severe acute respiratory infections (SARI) definition according to World Health Organization criteriatested for any reason and found to have and had laboratory proven influenza September 21, 2015 through March 20, 2018. Pulmonary, cardiac, renal, hematologic and neurologic complications were recorded. Results were compared by type, age, gender and health status. Multivariate analysis was used to analyze risk factors for complications and death.

RESULTS

Of 11,080 enrolled patients, 10,046 (90.7 %) were inpatients, 2254 (20.4 %) were children, 8403 (75.8 %) had influenza A, 2599 (23.5 %) had influenza B, and 78 (0.7 %) had unidentified types. Fever was less common in older patients (OR 0.99; 95 % CI 0.98-0.99, p < 0.001 and in those with comorbidity (OR 0.87; 95 % CI 0.77-0.97, p = 0.013). Although the rate of complications was lower with A(H1N1) pdm09 influenza than with A(H3N2) infection (12.8 % versus 15.6 %, p = 0.001), the mortality rate was higher (7.0 % versus 3.0 %, p < 0.001). Complications occurred more often during late versus early influenza season (OR 1.22; 95 % CI 1.08-1.37, p = 0.002). Patients with type B influenza (OR 0.85; 95 % CI 0.74-0.98, p = 0.025), or who presented with sore throat (OR 0.74; 95 % CI 0.65-0.84, p < 0.001) were less likely to develop complications. The risk of developing complications was increased in patients who had chronic heart disease (OR 1.51; 95 % CI 1.29-1.76, p < 0.001), chronic pulmonary disease (OR 1.62; 95 % CI 1.37-1.91, p < 0.001), diabetes (OR 1.24; 95 % CI 1.03-1.50, p = 022), or epilepsy (OR 1.55; 95 % CI 1.17-2.05). Older age and male gender increased the risk of death but not of complications.

CONCLUSIONS

The clinical features, complications and outcomes of influenza vary by age and by viral type and sub-type. Comorbidites appear to be more important than age in predicting complications.

Predisposing risk factors for COVID-19 infection: A case-control study

BACKGROUND

The Covid-19 epidemic in 2019 has created many public health problems. Literature that focuses on the risk factors of this issue is limited especially in developing countries. This study proposed to examine the risk factors of COVID-19 infection in the west area of Iran.

METHODS

This case-control study was conducted from February to April 2020 in Nahavand county, western Iran. Cases were all patients who were coronavirus positive and, the controls included people who had clinical signs consistent with COVID-19, but their test results were negative. Two controls were selected for every case. Multivariate logistic regression was applied to evaluate the effects of epidemiological aspects on the incidence of COVID-19.

RESULTS

Significant risk factors for COVID-19 infection based on the multivariable logistic regression model were male gender (OR=1.82, P=0.0.15), age group over 60 years (OR=2.04, P=0.017), living in urban areas (OR=1.79, P=0.018), being married (OR=2.08, P=0.022), having history of contact with the corona patients (OR=5.61, P=0.009), and comorbidities (OR=1.78, P=0.031).

CONCLUSION

This study highlighted the factors associated with the occurrence of COVID-19 infection. These findings may help guide recommendations for the protection of high-risk groups.

The National Influenza Surveillance System of Korea

Influenza is a very important respiratory infectious disease that causes seasonal epidemics and pandemics. A well-organized surveillance system is necessary to monitor and respond effectively to the epidemiologic features of influenza. Korea currently operates a national influenza surveillance system based on the clinical sentinel surveillance system, laboratory sentinel surveillance system, and hospitalization and mortality surveillance system. However, there is a need for a better national surveillance system due to a demand for various pieces of information related to influenza. This article discusses the general aspects of influenza surveillance systems and the future direction of the national influenza surveillance system of Korea.

C-reactive protein as a biomarker of severe H1N1 influenza

Background

C-reactive protein (CRP) is an acute-phase reactant downstream of the pro-inflammatory cytokines released during influenza infection. However, the role of this inflammatory marker in influenza severity and complications is yet to be elucidated.

Objectives

We aim to systematically review and evaluate the levels of CRP in severe and non-severe H1N1 influenza cases and assess its utility as a biomarker in predicting the severity of infection.

Methods

We conducted a comprehensive search in Ovid MEDLINE, Ovid MEDLINE (R) Epub ahead of Print, Embase and Embase Classic to identify human studies reporting measurements of CRP levels in patients infected with H1N1 influenza at various levels of disease severity.

Results

Our search identified ten studies eligible for inclusion in this systematic review. The results of the data analysis show that the average CRP levels upon diagnosis were significantly higher (P < 0.05) in patients who developed severe H1N1 influenza compared to their counterparts with a no severe disease. Furthermore, levels of CRP were associated with the degree of H1N1 severity. Subjects with H1N1-related pneumonia and patients who were hospitalized or died of the disease complications, respectively, had 1.4- and 2.5-fold significantly higher CRP levels (P < 0.05) than those with no severe disease outcome.

Conclusion

CRP levels have been consistently shown to be significantly higher in H1N1 influenza patients who develop a severe disease outcome. The resuts of the present study suggest that serum CRP can be employed—in combination with other biomarkers—to predict the complications of H1N1 influenza.

Electronic supplementary material

The online version of this article (10.1007/s00011-018-1188-x) contains supplementary material, which is available to authorized users.

Literature review of the epidemiology of influenza B disease in 15 countries in the Asia-Pacific region

Influenza control strategies focus on the use of trivalent influenza vaccines containing two influenza A virus subtypes and one of the two circulating influenza type B lineages (Yamagata or Victoria). Mismatches between the vaccine B lineage and the circulating lineage have been regularly documented in many countries, including those in the Asia‐Pacific region. We conducted a literature review with the aim of understanding the relative circulation of influenza B viruses in Asia‐Pacific countries. PubMed and Western Pacific Region Index Medicus were searched for relevant articles on influenza type B published since 1990 in English language for 15 Asia‐Pacific countries. Gray literature was also accessed. From 4834 articles identified, 121 full‐text articles were analyzed. Influenza was reported as an important cause of morbidity in the Asia‐Pacific region, affecting all age groups. In all 15 countries, influenza B was identified and associated with between 0% and 92% of laboratory‐confirmed influenza cases in any one season/year. Influenza type B appeared to cause more illness in children aged between 1 and 10 years than in other age groups. Epidemiological data for the two circulating influenza type B lineages remain limited in several countries in the Asia‐Pacific, although the co‐circulation of both lineages was seen in countries where strain surveillance data were available. Mismatches between circulating B lineages and vaccine strains were observed in all countries with available data. The data suggest that a shift from trivalent to quadrivalent seasonal influenza vaccines could provide additional benefits by providing broader protection.

Effects of influenza immunization on pneumonia in the elderly

Influenza virus is a common pathogen implicated in respiratory tract infections, annually affecting up to 20% of the general population, and pneumonia is a leading cause of death after influenza infection. Post-influenza pneumonia is especially common in the elderly and chronically ill patients. The risk of post-influenza pneumonia is significantly increased according to the number of concurrent comorbidities. Vaccination is the primary measure used to abate influenza epidemics and associated complications. In meta-analyses, influenza vaccine significantly reduces pneumonia- and influenza-related hospitalizations, with a vaccine effectiveness of 25-53%. However, considering the poor effectiveness of conventional influenza vaccines in the elderly, several highly immunogenic influenza vaccines have been developed. Further evaluations of the comparative effectiveness of diverse vaccine formulations are warranted to assess their utility for preventing influenza infection, post-influenza pneumonia, and related hospitalization/mortality. Based on cost-effectiveness and budget impact analysis, influenza vaccination strategies should be tailored in the elderly.

Incidence and Risk Factors of Pneumonia in Hospitalized Patients with Seasonal Influenza A or B

BACKGROUND

Most patients with influenza recover spontaneously or following treatment with an anti-viral agent, but some patients experience pneumonia requiring hospitalization. We conducted a retrospective review to determine the incidence and risk factors of pneumonia in hospitalized patients with influenza A or B.

METHODS

A total of 213 patients aged 18 years or older and hospitalized with influenza between January 2012 and January 2015 were included in this study. A reverse-transcriptase polymerase chain reaction assay was used to detect the influenza A or B virus in the patients' sputum samples. We collected demographic and laboratory data, combined coexisting diseases, and radiologic findings.

RESULTS

The incidence of pneumonia was higher in patients in the influenza A group compared to those in the influenza B group (68.6% vs. 56.9%), but this difference was not statistically significant. The presence of underlying respiratory disease was significantly associated with pneumonia in the influenza A group (adjusted odds ratio [OR], 3.975; 95% confidence interval [CI], 1.312-12.043; p=0.015). In the influenza B group, the white blood cell count (adjusted OR, 1.413; 95% CI, 1.053-1.896; p=0.021), platelet count (adjusted OR, 0.988; 95% CI, 0.978-0.999; p=0.027), and existence of an underlying medical disease (adjusted OR, 15.858; 95% CI, 1.757-143.088; p=0.014) were all significantly associated with pneumonia in multivariate analyses.

CONCLUSION

The incidence of pneumonia was 65.7% in hospitalized patients with influenza A or B. The risk factors of pneumonia differed in hospitalized patients with influenza A or B.

The Role of Influenza in the Delay between Low Temperature and Ischemic Heart Disease: Evidence from Simulation and Mortality Data from Japan

Many studies have found that cardiovascular deaths mostly occur within a few days of exposure to heat, whereas cold-related deaths can occur up to 30 days after exposure. We investigated whether influenza infection could explain the delayed cold effects on ischemic heart diseases (IHD) as they can trigger IHD. We hypothesized two pathways between cold exposure and IHD: a direct pathway and an indirect pathway through influenza infection. We created a multi-state model of the pathways and simulated incidence data to examine the observed delayed patterns in cases. We conducted cross-correlation and time series analysis with Japanese daily pneumonia and influenza (P&I) mortality data to help validate our model. Simulations showed the IHD incidence through the direct pathway occurred mostly within 10 days, while IHD through influenza infection peaked at 4–6 days, followed by delayed incidences of up to 20–30 days. In the mortality data from Japan, P&I lagged IHD in cross-correlations. Time series analysis showed strong delayed cold effects in the older population. There was also a strong delay on intense days of influenza which was more noticeable in the older population. Influenza can therefore be a plausible explanation for the delayed association between cold exposure and cardiovascular mortality.

The antibody response to influenza vaccination is not impaired in type 2 diabetics

BACKGROUND

Diabetics are considered to be at high risk for complications from influenza infection and type 2 diabetes is a significant comorbidity of obesity. Obesity is an independent risk factor for complications from infection with influenza. Annual vaccination is considered the best strategy for protecting against influenza infection and it's complications. Our previous study reported intact antibody responses 30 days post vaccination in an obese population. This study was designed to determine the antibody response to influenza vaccination in type 2 diabetics.

METHODS

Subjects enrolled were 18 or older without immunosuppressive diseases or taking immunosuppressive medications. A pre-vaccination blood draw was taken at time of enrollment, the subjects received the influenza vaccine and returned 28-32 days later for a post-vaccination blood draw. Height and weight were also obtained at the first visit and BMI was calculated. Antibody levels to the vaccine were determined by both ELISA and hemagglutination inhibition (HAI) assays.

RESULTS

As reported in our previous work, obesity positively correlates with the influenza antibody response (p=0.02), while age was negatively correlated with antibody response (p<0.001). In both year 1 and year 2 of our study there was no significant difference in the percentage of the type 2 diabetic subjects classified as seroprotected or a responder to the influenza vaccine compared to the non-diabetic subjects.

CONCLUSIONS

These data are important because they demonstrate that diabetics, considered a high risk group during influenza season, are able to mount an antibody response to influenza vaccination that may protect them from influenza infection.

Technical guidelines for the application of seasonal influenza vaccine in China (2014-2015)

Influenza, caused by the influenza virus, is a respiratory infectious disease that can severely affect human health. Influenza viruses undergo frequent antigenic changes, thus could spread quickly. Influenza causes seasonal epidemics and outbreaks in public gatherings such as schools, kindergartens, and nursing homes. Certain populations are at risk for severe illness from influenza, including pregnant women, young children, the elderly, and people in any ages with certain chronic diseases.