Covid-19 y gripe de 1918-1919: paralelos históricos, preguntas y respuestas / Covid-19 and the 1918-1919 influenza: historical parallels, questions and answers

Resumen El desarrollo de la pandemia de la covid-19 ha motivado un renovado interés por la gripe de 1918-1919 para buscar elementos que facilitaran la comprensión de la experiencia presente, pero también como oportunidad para reevaluar la grave crisis sanitaria del siglo XX a la luz de lo que estamos viviendo. En este contexto y con ese objetivo se inserta esta reflexión histórica sobre estos dos fenómenos pandémicos, que muestra los paralelismos existentes y la necesidad de una toma de conciencia de que nuestro modelo de sociedad está en crisis y se requiere una transformación profunda.

Abstract The rise of the covid-19 pandemic has led to renewed interest in the 1918-1919 influenza in search of aspects that might help us understand the current situation, but also as an opportunity to re-evaluate the serious twentieth-century health crisis in light of what we are experiencing now. In this context and with that goal, this historical reflection shows the parallels that exist and the need for a realization that our model of society is undergoing a crisis and requires profound transformation.

[Covid-19 and the 1918-1919 influenza: historical parallels, questions and answers]. / Covid-19 y gripe de 1918-1919: paralelos históricos, preguntas y respuestas.

The rise of the covid-19 pandemic has led to renewed interest in the 1918-1919 influenza in search of aspects that might help us understand the current situation, but also as an opportunity to re-evaluate the serious twentieth-century health crisis in light of what we are experiencing now. In this context and with that goal, this historical reflection shows the parallels that exist and the need for a realization that our model of society is undergoing a crisis and requires profound transformation.

El desarrollo de la pandemia de la covid-19 ha motivado un renovado interés por la gripe de 1918-1919 para buscar elementos que facilitaran la comprensión de la experiencia presente, pero también como oportunidad para reevaluar la grave crisis sanitaria del siglo XX a la luz de lo que estamos viviendo. En este contexto y con ese objetivo se inserta esta reflexión histórica sobre estos dos fenómenos pandémicos, que muestra los paralelismos existentes y la necesidad de una toma de conciencia de que nuestro modelo de sociedad está en crisis y se requiere una transformación profunda.

The "saddest repudiation" redux: Structural racism and the unlearned lesson of 1918.

The COVID-19 pandemic reveals how the systems and structures of racism devastate the health and well-being of people of color. The debate is an old one and the lesson we have yet to learn was tragically apparent a century ago during the 1918-1919 influenza pandemic. Any history of structural racism in America must begin with the chronicles of African Americans, Native Alaskans, and Indigenous North Americans as they were the originally enslaved and displaced people, subjected to overt and covert policies of oppression ever since. The experiences of Native Alaskans of Bristol Bay Alaska in 1918-1919 present a parallel, illuminating a wrenching example of structural racism that cost lives and impoverished society, then as now. Proven policy solutions exist to remove the structures that produce inequitable health outcomes, but implementing them will require public health officials and policymakers to take multidisciplinary policy actions, to find policy opportunities for change to be made, and, likely, a change in the political environment. The first exists now, the second is afforded because of the current pandemic and the urgent need for policy solutions, and the third is likely coming soon.

Historical Insights on Coronavirus Disease 2019 (COVID-19), the 1918 Influenza Pandemic, and Racial Disparities: Illuminating a Path Forward.

The coronavirus disease 2019 (COVID-19) pandemic is exacting a disproportionate toll on ethnic minority communities and magnifying existing disparities in health care access and treatment. To understand this crisis, physicians and public health researchers have searched history for insights, especially from a great outbreak approximately a century ago: the 1918 influenza pandemic. However, of the accounts examining the 1918 influenza pandemic and COVID-19, only a notable few discuss race. Yet, a rich, broader scholarship on race and epidemic disease as a "sampling device for social analysis" exists. This commentary examines the historical arc of the 1918 influenza pandemic, focusing on black Americans and showing the complex and sometimes surprising ways it operated, triggering particular responses both within a minority community and in wider racial, sociopolitical, and public health structures. This analysis reveals that critical structural inequities and health care gaps have historically contributed to and continue to compound disparate health outcomes among communities of color. Shifting from this context to the present, this article frames a discussion of racial health disparities through a resilience approach rather than a deficit approach and offers a blueprint for approaching the COVID-19 crisis and its afterlives through the lens of health equity.

Seasonal influenza vaccination policies in the Eastern Mediterranean Region: Current status and the way forward.

BACKGROUND: The World Health Organization recommends annual influenza vaccination, especially in high-risk groups. Little is known about the adoption and implementation of influenza vaccination policies in the Eastern Mediterranean Region. METHODS: A survey was distributed to country representatives at the ministries of health of the 22 countries of the Region between December 2016 and February 2017 to capture data on influenza immunization policies, recommendations, and practices in place. RESULTS: Of the 20 countries that responded to the survey, 14 reported having influenza immunization policies during the 2015/2016 influenza season. All countries with an influenza immunization policy recommended vaccination for people with chronic medical conditions, healthcare workers and pilgrims. Two of the 20 countries did not target pregnant women. Eight countries used the northern hemisphere formulation, one used the southern hemisphere formulation and nine used both. Vaccination coverage was not monitored by all countries and for all target groups. Where reported, coverage of a number of target groups (healthcare workers, children) was generally low. Data on the burden of influenza and vaccine protection are scarce in the Region. CONCLUSIONS: Despite widespread policy recommendations on influenza vaccination, attaining high coverage rates remains a challenge in the Eastern Mediterranean Region. Tackling disparities in influenza vaccine accessibility and strengthening surveillance systems may increase influenza vaccine introduction and use.

Sex- and age-based differences in mortality during the 1918 influenza pandemic on the island of Newfoundland.

OBJECTIVES: Our aim was to understand sex- and age-based differences in mortality during the 1918 influenza pandemic on the island of Newfoundland. The pandemic's impact on different age groups has been the focus of other research, but sex-based differences in mortality are rarely considered. Aspects of social organization, labor patterns, and social behaviors that contribute to mortality between males and females at all ages are used to explain observed mortality patterns. METHODS: Recorded pneumonia and influenza deaths on the island (n = 1871) were used to calculate cause-specific death rates and to evaluate differences in sex-based mortality. Mortality levels in 17 districts and four regions (Avalon, North, South, and West) were compared using standardized mortality ratios (SMRs). A logistic regression model was fit to determine in which regions sex-based mortality could be predicted using age and region as interactive predictors. RESULTS: Differences in sex-based mortality varied across regions; they were not significant for the aggregate population. SMRs were also variable, with no significant sex-based differences. Sex-based differences were highly variable within regions. Results from a logistic regression analysis suggest that females in the South region may have experienced a higher probability of death than other island residents. CONCLUSIONS: Mortality analysis for aggregate populations homogenizes important epidemiologic patterns. Men and women did not experience the 1918 influenza pandemic in the same way, and by analyzing data at the regional and district geographic levels, patterns emerge that can be explained by the economies and social organization of the people who lived there.

Readiness for Responding to a Severe Pandemic 100 Years After 1918.

The 1918 H1N1 pandemic caused an unprecedented number of deaths worldwide. The tools to deal with the global emergency were limited; there were insufficient surveillance systems and a dearth of diagnostic, treatment, and prevention options. With continuing focus on pandemic planning, technologic advances in surveillance, vaccine capabilities, and 21st century medical care and countermeasures, we are more prepared for a severe pandemic than people were 100 years ago; however, notable gaps remain.

Protective Measures for Humans against Avian Influenza A(H5N8) Outbreaks in 22 European Union/European Economic Area Countries and Israel, 2016-17.

We sought to better understand national approaches for managing potential human health risks during outbreaks of infection with avian influenza A(H5N8) virus during 2016-17. Twenty-three countries in the Union/European Economic Area and Israel participated in this study. Risk to the general public was assessed as low in 18 countries and medium in 1 country. Of 524 exposed persons identified, 274 were passively monitored and 250 were actively monitored. Of 29 persons tested, all were negative for H5N8 virus. Vaccination and antiviral drug recommendations varied across countries. A high level of personal protection was recommended although a low risk was assessed. No transmission of this virus to humans was identified.

Social Class and Excess Mortality in Sweden During the 1918 Influenza Pandemic.

Consensus is lacking in the literature about the role of socioeconomic factors on influenza-associated deaths during the 1918 pandemic. Although some scholars have found that social factors were important, others have not. In this study, we analyzed differences in excess mortality by social class in Sweden during the 1918 pandemic. We analyzed individual-level mortality of the entire population aged 30-59 years by combining information from death records with census data on occupation. Social class was measured by an occupation-based class scheme. Excess mortality during the pandemic was measured as the number of deaths relative to the number occurring in the same month the year before. Social class differences in numbers of deaths were modeled using a complementary log-log model that was adjusted for potential confounding at the family, the residential (urban/rural), and the county levels. We found notable class differences in excess mortality but no perfect class gradient. Class differences were somewhat larger for men than for women.

How close are countries of the WHO European Region to achieving the goal of vaccinating 75% of key risk groups against influenza? Results from national surveys on seasonal influenza vaccination programmes, 2008/2009 to 2014/2015.

BACKGROUND: Influenza vaccination is recommended especially for persons at risk of complications. In 2003, the World Health Assembly urged Member States (MS) to increase vaccination coverage to 75% among older persons by 2010. OBJECTIVE: To assess progress towards the 2010 vaccination goal and describe seasonal influenza vaccination recommendations in the World Health Organization (WHO) European Region. METHODS: Data on seasonal influenza vaccine recommendations, dose distribution, and target group coverage were obtained from two sources: European Union and European Economic Area MS data were extracted from influenza vaccination surveys covering seven seasons (2008/2009-2014/2015) published by the Vaccine European New Integrated Collaboration Effort and European Centre for Disease Prevention and Control. For the remaining WHO European MS, a separate survey on policies and uptake for all seasons (2008/2009-2014/2015) was distributed to national immunization programmes in 2015. RESULTS: Data was available from 49 of 53 MS. All but two had a national influenza vaccination policy. High-income countries distributed considerably higher number of vaccines per capita (median; 139.2 per 1000 population) compared to lower-middle-income countries (median; 6.1 per 1000 population). Most countries recommended vaccination for older persons, individuals with chronic disease, healthcare workers, and pregnant women. Children were included in < 50% of national policies. Only one country reached 75% coverage in older persons (2014/2015), while a number of countries reported declining vaccination uptake. Coverage of target groups was overall low, but with large variations between countries. Vaccination coverage was not monitored for several groups. CONCLUSIONS: Despite policy recommendations, influenza vaccination uptake remains suboptimal. Low levels of vaccination is not only a missed opportunity for preventing influenza in vulnerable groups, but could negatively affect pandemic preparedness. Improved understanding of barriers to influenza vaccination is needed to increase uptake and reverse negative trends. Furthermore, implementation of vaccination coverage monitoring is critical for assessing performance and impact of the programmes.

Burden of medically attended influenza infection and cases averted by vaccination - United States, 2013/14 through 2015/16 influenza seasons.

BACKGROUND: In addition to preventing hospitalizations and deaths due to influenza, influenza vaccination programs can reduce the burden of outpatient visits for influenza. We estimated the incidence of medically-attended influenza at three geographically diverse sites in the United States, and the cases averted by vaccination, for the 2013/14 through 2015/16 influenza seasons. METHODS: We defined surveillance populations at three sites from the United States Influenza Vaccine Effectiveness Network. Among these populations, we identified outpatient visits laboratory-confirmed influenza via active surveillance, and identified all outpatient visits for acute respiratory illness from healthcare databases. We extrapolated the total number of outpatient visits for influenza from the proportion of surveillance visits with a positive influenza test. We combined estimates of incidence, vaccine coverage, and vaccine effectiveness to estimate outpatient visits averted by vaccination. RESULTS: Across the three sites and seasons, incidence of medically attended influenza ranged from 14 to 54 per 1000 population. Incidence was highest in children aged 6 months to 9 years (33 to 70 per 1000) and lowest in adults aged 18-49 years (21 to 27 per 1000). Cases averted ranged from 9 per 1000 vaccinees (Washington, 2014/15) to 28 per 1000 (Wisconsin, 2013/14). DISCUSSION: Seasonal influenza epidemics cause a considerable burden of outpatient medical visits. The United States influenza vaccination program has caused meaningful reductions in outpatient visits for influenza, even in years when the vaccine is not well-matched to the dominant circulating influenza strain.

Antigenic Patterns and Evolution of the Human Influenza A (H1N1) Virus.

The influenza A (H1N1) virus causes seasonal epidemics that result in severe illnesses and deaths almost every year. A deep understanding of the antigenic patterns and evolution of human influenza A (H1N1) virus is extremely important for its effective surveillance and prevention. Through development of antigenicity inference method for human influenza A (H1N1), named PREDAC-H1, we systematically mapped the antigenic patterns and evolution of the human influenza A (H1N1) virus. Eight dominant antigenic clusters have been inferred for seasonal H1N1 viruses since 1977, which demonstrated sequential replacements over time with a similar pattern in Asia, Europe and North America. Among them, six clusters emerged first in Asia. As for China, three of the eight antigenic clusters were detected in South China earlier than in North China, indicating the leading role of South China in H1N1 transmission. The comprehensive view of the antigenic evolution of human influenza A (H1N1) virus can help formulate better strategy for its prevention and control.

The influenza pandemic of 1918-1919 in Sri Lanka: its demographic cost, timing, and propagation.

BACKGROUND: As an island and a former British colony, Sri Lanka is a case of special interest for the study of 1918-1919 influenza pandemic because of its potential for isolation from as well as integration into the world epidemiologic system. OBJECTIVES: To estimate population loss attributable to the influenza pandemic and weekly district-level excess mortality from the pandemic to analyze its spread across the island. METHODS: To measure population loss, we estimated a population growth model using a panel of 100 district-level observations on population for five consecutive censuses from 1891 to 1931, allowing for a one-time drop in population in 1918-1919. To estimate weekly excess mortality from the pandemic, we estimated a seasonally adjusted weekly time series of district-specific mortality estimates from vital registration records, ranked them, and plotted the ranks on weekly maps to create a picture of the geographic pattern of propagation across Sri Lanka. RESULTS: Total loss of population from the influenza pandemic was 307 000 or approximately 6·7% of the population. The pandemic peaked in two discrete (northern and southern) regions in early October of 1918 and in a third (central) region in early March 1919. CONCLUSIONS: The population loss estimate is significantly higher than earlier estimates of mortality from the pandemic in Sri Lanka, suggesting underreporting of influenza-attributable deaths and a role for influenza-related fertility declines. The spatial pattern of peak mortality indicates the presence of two distinct entry points and three distinct epidemiologic regions, defined by population density and ethnicity, in colonial Sri Lanka.

Excess healthcare burden during 1918-1920 influenza pandemic in Taiwan: implications for post-pandemic preparedness.

BACKGROUND: It is speculated that the 2009 pandemic H1N1 influenza virus might fall into a seasonal pattern during the current post-pandemic period with more severe clinical presentation for high-risk groups identified during the 2009 pandemic. Hence the extent of likely excess healthcare needs during this period must be fully considered. We will make use of the historical healthcare record in Taiwan during and after the 1918 influenza pandemic to ascertain the scope of potential excess healthcare burden during the post-pandemic period. METHODS: To establish the healthcare needs after the initial wave in 1918, the yearly healthcare records (hospitalizations, outpatients, etc.) in Taiwan during 1918-1920 are compared with the corresponding data from the adjacent "baseline" years of 1916, 1917, 1921, and 1922 to estimate the excess healthcare burden during the initial outbreak in 1918 and in the years immediately after. RESULTS: In 1918 the number of public hospital outpatients exceeded the yearly average of the baseline years by 20.11% (95% CI: 16.43, 25.90), and the number of hospitalizations exceeded the corresponding yearly average of the baseline years by 12.20% (10.59, 14.38), while the excess number of patients treated by the public medics was statistically significant at 32.21% (28.48, 39.82) more than the yearly average of the baseline years. For 1920, only the excess number of hospitalizations was statistically significant at 19.83% (95% CI: 17.21, 23.38) more than the yearly average of the baseline years. CONCLUSIONS: Considerable extra burden with significant loss of lives was reported in 1918 by both the public medics system and the public hospitals. In comparison, only a substantial number of excess hospitalizations in the public hospitals was reported in 1920, indicating that the population was relatively unprepared for the first wave in 1918 and did not fully utilize the public hospitals. Moreover, comparatively low mortality was reported by the public hospitals and the public medics during the second wave in 1920 even though significantly more patients were hospitalized, suggesting that there had been substantially less fatal illnesses among the hospitalized patients during the second wave. Our results provide viable parameters for assessing healthcare needs for post-pandemic preparedness.

Pandemic H1N1 2009 ('swine flu'): diagnostic and other challenges.

Pandemic H1N1 2009 ('swine flu') virus was 'the virus of the year 2009' because it affected the lives of many people in this year. H1N1 was first described in California in April 2009 and spread very rapidly all over the globe. The fast global penetration of the swine flu caused the WHO in Geneva to call the infection with H1N1 a new pandemic with a rapid escalation of the different pandemic phases that ended on 11 June 2009, with the declaration of phase 6 (full-blown pandemic). This had far-reaching consequences for the local health authorities in the different affected countries and created awareness in the public and fear in the experts and even more so in many lay people. The consequences were: setting up reliable diagnostic tests as soon as possible; enhanced production, distribution and stock creation of the few drugs that were available to treat newly infected persons; and development, production, distribution and stock creation of new and appropriate anti-H1N1 swine flu vaccines. This all resulted in enormous costs in the local healthcare systems and also required smart and diligent logistics, because demand for all this was, in most cases, much higher than availability. Fortunately, the pandemic ended quite quickly (there was no 'second wave' as had been anticipated by some experts) and the death toll was moderate, compared with other influenza pandemic in the past and even to the regular annual appearance of the seasonal flu. This favorable outcome, however, provoked some harsh criticism that the WHO and healthcare systems in general had over-reacted and by doing so, a lot of money was thrown out of the window. This article describes the history of the H1N1 pandemic, the diagnostic challenges and resolutions, touches on treatment and vaccination very briefly and also comments on the criticism and arguments that came up immediately at the end and following the termination of the pandemic situation.

Agent-based modeling of the spread of the 1918-1919 flu in three Canadian fur trading communities.

OBJECTIVES: Previous attempts to study the 1918-1919 flu in three small communities in central Manitoba have used both three-community population-based and single-community agent-based models. These studies identified critical factors influencing epidemic spread, but they also left important questions unanswered. The objective of this project was to design a more realistic agent-based model that would overcome limitations of earlier models and provide new insights into these outstanding questions. METHODS: The new model extends the previous agent-based model to three communities so that results can be compared to those from the population-based model. Sensitivity testing was conducted, and the new model was used to investigate the influence of seasonal settlement and mobility patterns, the geographic heterogeneity of the observed 1918-1919 epidemic in Manitoba, and other questions addressed previously. RESULTS: Results confirm outcomes from the population-based model that suggest that (a) social organization and mobility strongly influence the timing and severity of epidemics and (b) the impact of the epidemic would have been greater if it had arrived in the summer rather than the winter. New insights from the model suggest that the observed heterogeneity among communities in epidemic impact was not unusual and would have been the expected outcome given settlement structure and levels of interaction among communities. CONCLUSIONS: Application of an agent-based computer simulation has helped to better explain observed patterns of spread of the 1918-1919 flu epidemic in central Manitoba. Contrasts between agent-based and population-based models illustrate the advantages of agent-based models for the study of small populations.

Public health and medical responses to the 1957-58 influenza pandemic.

As the U.S. prepares to respond this fall and winter to pandemic (H1N1) 2009, a review of the 1957-58 pandemic of Asian influenza (H2N2) could be useful for planning purposes because of the many similarities between the 2 pandemics. Using historical surveillance reports, published literature, and media coverage, this article provides an overview of the epidemiology of and response to the 1957-58 influenza pandemic in the U.S., during which an estimated 25% of the population became infected with the new pandemic virus strain. While it cannot be predicted with absolute certainty how the H1N1 pandemic might play out in the U.S. this fall, lessons from the 1957-58 influenza pandemic provide useful and practical insights for current planning and response efforts.