Age-specific Case Fatality Ratio Research Articles

Epidemiological features and trends in the mortality rates of 10 notifiable respiratory infectious diseases in China from 2004 to 2020: Based on national surveillance.

The aim of this study is to describe, visualize, and compare the trends and epidemiological features of the mortality rates of 10 notifiable respiratory infectious diseases in China from 2004 to 2020. Data were obtained from the database of the National Infectious Disease Surveillance System (NIDSS) and reports released by the National and local Health Commissions from 2004 to 2020. Spearman correlations and Joinpoint regression models were used to quantify the temporal trends of RIDs by calculating annual percentage changes (APCs) in the rates of mortality. The overall mortality rate of RIDs was stable across China from 2004 to 2020 (R = -0.38, P = 0.13), with an APC per year of -2.2% (95% CI: -4.6 to 0.3; P = 0.1000). However, the overall mortality rate of 10 RIDs in 2020 decreased by 31.80% (P = 0.006) compared to the previous 5 years before the COVID-19 pandemic. The highest mortality occurred in northwestern, western, and northern China. Tuberculosis was the leading cause of RID mortality, and mortality from tuberculosis was relatively stable throughout the 17 years (R = -0.36, P = 0.16), with an APC of -1.9% (95% CI -4.1 to 0.4, P = 0.1000). Seasonal influenza was the only disease for which mortality significantly increased (R = 0.73, P = 0.00089), with an APC of 29.70% (95% CI 16.60-44.40%; P = 0.0000). The highest yearly case fatality ratios (CFR) belong to avian influenza A H5N1 [687.5 per 1,000 (33/48)] and epidemic cerebrospinal meningitis [90.5748 per 1,000 (1,010/11,151)]. The age-specific CFR of 10 RIDs was highest among people over 85 years old [13.6551 per 1,000 (2,353/172,316)] and was lowest among children younger than 10 years, particularly in 5-year-old children [0.0552 per 1,000 (58/1,051,178)]. The mortality rates of 10 RIDs were relatively stable from 2004 to 2020 with significant differences among Chinese provinces and age groups. There was an increased mortality trend for seasonal influenza and concerted efforts are needed to reduce the mortality rate of seasonal influenza in the future.

COVID-19-related deaths: a 2-year inter-wave comparison of mortality data from Germany.

The severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) has caused substantial mortality worldwide. We investigated clinical and demographic features of COVID-19-related deaths that occurred between March 2020 and January 2022 in Regensburg, Germany. We compared data across four consecutive time periods: March 2020 to September 2020 (period 1), October 2020 to February 2021 (period 2), March 2021 to August 2021 (period 3), and September 2021 to January 2022 (period 4). Overall, 405 deaths in relation to COVID-19 were reported. The raw case fatality ratio (CFR) was 0.92. In periods 1 to 4, the CFRs were 1.70%, 2.67%, 1.06%, and 0.36%. The age-specific CFR and mortality were highest in persons aged ≥ 80years in period 2 while mortality in younger cases increased with time. The median age at death was 84years and it varied slightly across periods. Around 50% of cases of death were previously hospitalized. In all time periods, the cause of death was mostly attributed to COVID-19. Over the four periods, we did not find significant changes in the distribution of sex and risk factors for severe disease. The most frequent risk factor was cardio-circulatory disease. In conclusion, the CFR decreased over time, most prominently for period 4. Mortality was considerable and younger cases were increasingly at risk.

The Relationship between Tuberculosis and Influenza Death during the Influenza (H1N1) Pandemic from 1918-19

The epidemiological mechanisms behind the W-shaped age-specific influenza mortality during the Spanish influenza (H1N1) pandemic 1918-19 have yet to be fully clarified. The present study aimed to develop a formal hypothesis: tuberculosis (TB) was associated with the W-shaped influenza mortality from 1918-19. Three pieces of epidemiological information were assessed: (i) the epidemic records containing the age-specific numbers of cases and deaths of influenza from 1918-19, (ii) an outbreak record of influenza in a Swiss TB sanatorium during the pandemic, and (iii) the age-dependent TB mortality over time in the early 20th century. Analyzing the data (i), we found that the W-shaped pattern was not only seen in mortality but also in the age-specific case fatality ratio, suggesting the presence of underlying age-specific risk factor(s) of influenza death among young adults. From the data (ii), TB was shown to be associated with influenza death (P = 0.09), and there was no influenza death among non-TB controls. The data (iii) were analyzed by employing the age-period-cohort model, revealing harvesting effect in the period function of TB mortality shortly after the 1918-19 pandemic. These findings suggest that it is worthwhile to further explore the role of TB in characterizing the age-specific risk of influenza death.

New Variants and Age Shift to High Fatality Groups Contribute to Severe Successive Waves in the 2009 Influenza Pandemic in Taiwan

Past influenza pandemics have been characterized by the signature feature of multiple waves. However, the reasons for multiple waves in a pandemic are not understood. Successive waves in the 2009 influenza pandemic, with a sharp increase in hospitalized and fatal cases, occurred in Taiwan during the winter of 2010. In this study, we sought to discover possible contributors to the multiple waves in this influenza pandemic. We conducted a large-scale analysis of 4703 isolates in an unbiased manner to monitor the emergence, dominance and replacement of various variants. Based on the data from influenza surveillance and epidemic curves of each variant clade, we defined virologically and temporally distinct waves of the 2009 pandemic in Taiwan from May 2009 to April 2011 as waves 1 and 2, an interwave period and wave 3. Except for wave 3, each wave was dominated by one distinct variant. In wave 3, three variants emerged and co-circulated, and formed distinct phylogenetic clades, based on the hemagglutinin (HA) genes and other segments. The severity of influenza was represented as the case fatality ratio (CFR) in the hospitalized cases. The CFRs in waves 1 and 2, the interwave period and wave 3 were 6.4%, 5.1%, 15.2% and 9.8%, respectively. The results highlight the association of virus evolution and variable influenza severity. Further analysis revealed that the major affected groups were shifted in the waves to older individuals, who had higher age-specific CFRs. The successive pandemic waves create challenges for the strategic preparedness of health authorities and make the pandemic uncertain and variable. Our findings indicate that the emergence of new variants and age shift to high fatality groups might contribute potentially to the occurrence of successive severe pandemic waves and offer insights into the adjustment of national responses to mitigate influenza pandemics.

The epidemiology of herpes zoster and potential cost-effectiveness of vaccination in England and Wales

The epidemiology of herpes zoster and post-herpetic neuralgia (PHN) was quantified from a variety of data sources and the potential cost-effectiveness of vaccination assessed. The annual incidence and severity of zoster increases sharply with age, as measured by physician consultation and hospitalisation rates, average length of stay, average proportion of cases developing PHN and the age-specific case-fatality ratio. Combining these data with information on health related quality of life results in an estimated loss of 20 000 quality adjusted life years (QALYs) annually in England and Wales from herpes zoster (17 400 due to PHN). The current cost of treating herpes zoster associated disease is estimated to be £47.6m annually. Since both the health and economic burden are high, vaccination of the elderly is expected to be cost-effective under most scenarios, the attractiveness of immunisation increasing with age due to the increased burden of disease in the very elderly.

Epidemic measles in an isolated unvaccinated population, India.

Between June and September, 1986, an outbreak of measles occurred in Pilkhi Primary Health Centre area (population 56,000) in Tehri Garhwal district, Uttar Pradesh, India. Overall, 1092 cases were identified and 62 died; case-fatality ratio was 5.7%. Illness was restricted primarily to children below 15 years of age; 38% cases were in children under 5 and 58% between 5-14 years of age. To better characterize the outbreak, a survey was conducted in 13 affected villages. The age of the cases ranged from 5 months to 19 years (median = 7.0 years). The age-specific attack rates were 22.4%, 54.5%, 46.2% and 35.3% for children under 1, 1-4, 5-9, 10-14 years of age respectively. In as many as four villages, the attack rate in children below ten was 80% or more. Secondary attack rate among family members was 70%. Overall, 82% of children with measles developed complications which consisted mainly of pneumonia, diarrhoea and dysentery. The age-specific case-fatality ratios in infants and children 1-4 years of age were 23.1% and 11.5% respectively; thereafter the rates tended to decline with increasing age and was higher in females than in males (less than 0.05). Pneumonia which was a complication in 39% of measles cases contributed to 56% of deaths. Traditional beliefs and customs in the area were strong and did not encourage treatment of measles cases. Although a measles vaccination programme has been launched in India since 1985, only 30 districts could be covered during the first year and another 90 during 1986.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute bacterial meningitis in Cairo, Arab Republic of Egypt, 1 January 1971 through 31 December 1975.

Between 1 January 1971 and 31 December 1975, 1,333 patients with acute bacterial meningitis were admitted to the meningitis ward of the Abbassia Fever Hospital. These cases are tabulated by distribution of diagnosis, seasonal distribution, age and sex distribution, and age-specific case fatality ratio. Results are compared with those of other large series of cases reported from other parts of the world. The annual incidence of acute bacterial meningitis in Egypt varies widely. Recent data show this to be due to variations in the incidence of group A meningococcal meningitis. The study includes the declining phase of an epidemic of that disease and confirms a previously reported finding that the case fatality ratio in group A meningococcal meningitis varies inversely with the annual number of cases.