Disease mitigation measures in the control of pandemic influenza

Understanding if the reward is worth the influenza risk: The true cost of showing pigs

Influenza A virus transmission between pigs and humans has been reported periodically worldwide, and spillover events across the animal-human species barrier could lead to the next influenza pandemic. Swine exhibitions serve as a unique interface conducive to zoonotic disease transmission due to extensive commingling of pigs and humans for prolonged periods of time. The majority of zoonotic influenza A virus transmission in the United States has been linked to swine exhibitions, leading some to suggest additional controls for influenza A virus at the swine-human interface. Determining the value of the exhibition swine industry and gauging the financial impacts influenza A virus outbreaks could have on society, helps to inform adoption decisions of mitigation recommendations. This study estimates the total value of the exhibition swine industry in the United States and calculates the predicted costs of the most extreme mitigation strategy, cancelling swine exhibitions to reduce zoonotic influenza A virus transmission. Mixed methods, including a survey, were used to collect data and inform the study model. We estimated that the direct economic impact of the exhibition swine sector in 2018 was $1.2 billion. If pig shows were to be cancelled for one year, the estimated direct economic impact would be $357.1 million. A permanent, > 3-year ban on swine exhibitions would result in a $665 million economic impact, which is a 45% reduction from baseline. The direct economic impact of cancelling the swine show circuit could not be determined, as youth exhibitors may pursue alternative activities that cannot be precisely accounted for. However, the estimated loss to the swine industry justifies seeking enhanced mitigation to prevent disease transmission. Moreover, economic losses secondary to exhibition cancellations may explain hesitancy to participate in active influenza A virus surveillance efforts.

Rethinking the Ethics of the Covid-19 Pandemic Lockdowns

Public health responses to the Covid-19 pandemic included various measures to mitigate the spread of the virus. Among these, the most restrictive was a broad category referred to as "lockdowns." We argue that the reasoning offered in favor of extended lockdowns-those lasting several months or longer-did not adequately account for a host of countervailing considerations, including the impact on mental illness, education, employment, and marginalized communities as well as health, educational, and economic inequities. Furthermore, justifications offered for extended lockdowns set aside a basic tenet of public health ethics: restrictions on liberty and autonomy should be the least intrusive means of achieving the desired end. Since it is now clear that extended lockdowns cause severe harm to many vulnerable populations, the burden of proof is on those who would advocate for them, and there must be a much higher bar to implement an extended lockdown, with high-quality evidence that the benefit would substantially exceed its harm.

The pox of politics: Troesken's tradeoff reexamined

In The Pox of Liberty, Werner Troesken details the tradeoff between liberal institutions and communicable disease. According to Troesken, individual freedom presents a danger to the public health in the face of infectious disease, while constitutional constraints restrict the government's ability to implement effective policy. Contra Troesken, I argue that decision-makers, amidst a crisis of contagion, neglect intertemporal tradeoffs, thereby discounting long run costs while favoring short run policies. These policies, once implemented, are difficult to reverse due to the path dependent nature of political institutions. Irreversible and self-reinforcing growth in political institutions established to enhance health can have an unintended negative impact on health during future crises, where political agents must operate in a more cumbersome and error-prone institutional environment. Using events from the history of public health in the U.S. as support for my theory, I conclude that Troesken's alleged tradeoff ought to be met with greater skepticism.

Public health ethics: critiques of the "new normal"

The global response to the recent coronavirus pandemic has revealed an ethical crisis in public health. This article analyses key pandemic public health policies in light of widely accepted ethical principles: the need for evidence, the least restrictive/harmful alternative, proportionality, equity, reciprocity, due legal process, and transparency. Many policies would be considered unacceptable according to pre-pandemic norms of public health ethics. There are thus significant opportunities to develop more ethical responses to future pandemics. This paper serves as the introduction to this Special Issue of Monash Bioethics Review and provides background for the other articles in this collection.

Aggressive measures, rising inequalities, and mass formation during the COVID-19 crisis: An overview and proposed way forward

A series of aggressive restrictive measures were adopted around the world in 2020-2022 to attempt to prevent SARS-CoV-2 from spreading. However, it has become increasingly clear the most aggressive (lockdown) response strategies may involve negative side-effects such as a steep increase in poverty, hunger, and inequalities. Several economic, educational, and health repercussions have fallen disproportionately on children, students, young workers, and especially on groups with pre-existing inequalities such as low-income families, ethnic minorities, and women. This has led to a vicious cycle of rising inequalities and health issues. For example, educational and financial security decreased along with rising unemployment and loss of life purpose. Domestic violence surged due to dysfunctional families being forced to spend more time with each other. In the current narrative and scoping review, we describe macro-dynamics that are taking place because of aggressive public health policies and psychological tactics to influence public behavior, such as mass formation and crowd behavior. Coupled with the effect of inequalities, we describe how these factors can interact toward aggravating ripple effects. In light of evidence regarding the health, economic and social costs, that likely far outweigh potential benefits, the authors suggest that, first, where applicable, aggressive lockdown policies should be reversed and their re-adoption in the future should be avoided. If measures are needed, these should be non-disruptive. Second, it is important to assess dispassionately the damage done by aggressive measures and offer ways to alleviate the burden and long-term effects. Third, the structures in place that have led to counterproductive policies should be assessed and ways should be sought to optimize decision-making, such as counteracting groupthink and increasing the level of reflexivity. Finally, a package of scalable positive psychology interventions is suggested to counteract the damage done and improve humanity's prospects.

Adding a reaction-restoration type transmission rate dynamic-law to the basic SEIR COVID-19 model

The classical SEIR model, being an autonomous system of differential equations, has important limitations when representing a pandemic situation. Particularly, the geometric unimodal shape of the epidemic curve is not what is generally observed. This work introduces the βSEIR model, which adds to the classical SEIR model a differential law to model the variation in the transmission rate. It considers two opposite thrives generally found in a population: first, reaction to disease presence that may be linked to mitigation strategies, which tends to decrease transmission, and second, the urge to return to normal conditions that pulls to restore the initial value of the transmission rate. Our results open a wide spectrum of dynamic variabilities in the curve of new infected, which are justified by reaction and restoration thrives that affect disease transmission over time. Some of these dynamics have been observed in the existing COVID-19 disease data. In particular and to further exemplify the potential of the model proposed in this article, we show its capability of capturing the evolution of the number of new confirmed cases of Chile and Italy for several months after epidemic onset, while incorporating a reaction to disease presence with decreasing adherence to mitigation strategies, as well as a seasonal effect on the restoration of the initial transmissibility conditions.

Challenges of integrating economics into epidemiological analysis of and policy responses to emerging infectious diseases

COVID-19 has shown that the consequences of a pandemic are wider-reaching than cases and deaths. Morbidity and mortality are important direct costs, but infectious diseases generate other direct and indirect benefits and costs as the economy responds to these shocks: some people lose, others gain and people modify their behaviours in ways that redistribute these benefits and costs. These additional effects feedback on health outcomes to create a complicated interdependent system of health and non-health outcomes. As a result, interventions primarily intended to reduce the burden of disease can have wider societal and economic effects and more complicated and unintended, but possibly not anticipable, system-level influences on the epidemiological dynamics themselves. Capturing these effects requires a systems approach that encompasses more direct health outcomes. Towards this end, in this article we discuss the importance of integrating epidemiology and economic models, setting out the key challenges which such a merging of epidemiology and economics presents. We conclude that understanding people's behaviour in the context of interventions is key to developing a more complete and integrated economic-epidemiological approach; and a wider perspective on the benefits and costs of interventions (and who these fall upon) will help society better understand how to respond to future pandemics.

Rethinking COVID-19 and Beyond: Prevention, Remedies, and Recovery

In a relatively short timeframe, millions of deaths and illnesses associated with COVID-19 have been reported, accompanied by substantial economic losses, and overall, negatively impacting society. This experience should serve as a wakeup call to those in public health and healthcare, along with politicians and citizens: COVID-19 is considered a predictable and preventable disaster. While various reactive responses to address the pandemic were implemented, some with adverse effects, proactive measures in the years before COVID-19 were neglected. Predominately this involved the development of a preventable overfat pandemic, which played a key role in both rising rates of chronic disease, the comorbidities that increase the risk for COVID-19, along with associated inflammation and malnutrition. This increased the risk of infection in billions of people worldwide, which, in essence, primed society for high rates of COVID-19 infection. Excess body fat evolves primarily from poor nutrition, particularly the overconsumption of sugar and other refined carbohydrates, which replace the vital nutrients needed for optimal immune function. Sugar and refined carbohydrates must be considered the new tobacco, as these foods are also devoid of nutrients, and underly inflammatory chronic diseases. A balanced diet of nutrient-dense wholefood must be emphasized to combat infectious and inflammatory diseases. Implementing proactive preventive lifestyle changes must begin now, starting with simple, safe, and inexpensive dietary modifications that can quickly lead to a healthier population.

The SARS-CoV-2 Pandemic in High Income Countries Such as Canada: A Better Way Forward Without Lockdowns

The SARS-CoV-2 pandemic has caused tragic morbidity and mortality. In attempt to reduce this morbidity and mortality, most countries implemented population-wide lockdowns. Here we show that the lockdowns were based on several flawed assumptions, including "no one is protected until everyone is protected," "lockdowns are highly effective to reduce transmission," "lockdowns have a favorable cost-benefit balance," and "lockdowns are the only effective option." Focusing on the latter, we discuss that Emergency Management principles provide a better way forward to manage the public emergency of the pandemic. Specifically, there are three priorities including the following: first, protect those most at risk by separating them from the threat (mitigation); second, ensure critical infrastructure is ready for people who get sick (preparation and response); and third, shift the response from fear to confidence (recovery). We argue that, based on Emergency Management principles, the age-dependent risk from SARS-CoV-2, the minimal (at best) efficacy of lockdowns, and the terrible cost-benefit trade-offs of lockdowns, we need to reset the pandemic response. We can manage risk and save more lives from both COVID-19 and lockdowns, thus achieving far better outcomes in both the short- and long-term.

The Paradoxes of the Pandemic and World Inequalities

While causing over 150,000 deaths in Africa, the spread of the COVID-19 virus did not produce the expected hecatomb. Clearly, the crisis is not over and with the emergence of new variants, the death toll could increase significantly. So far, however, COVID-19 has caused fewer African victims than elsewhere. Explaining this reality remains difficult and speculative. It appears, however, that a major reason might be the continent’s very young population and the fact that it enjoys relatively low levels of obesity. These two factors have played a significant role in the high COVID-19 mortality rate in the most affected industrialized countries. In addition, many African countries have learned how to deal with health emergencies from their past experiences with other major pandemics. A final and more controversial explanation of the low death rate in the region is that in their fight against malaria, Africans have used hydroxychloroquine—a medicine that has allegedly curbed the effects of COVID-19—on a mass scale and for generations. COVID-19 has also had crippling consequences for the continent’s already debilitated economies and raised poverty to alarming levels. The pandemic has also highlighted the persistence of narrow nationalistic interests, as well as the massive inequalities of wealth and power that structure the global system. This is evident in the very uneven worldwide distribution of the COVID-19 vaccines.

The Type I interferon antiviral gene program is impaired by lockdown and preserved by caregiving

Previous research has linked perceived social isolation (loneliness) to reduced antiviral immunity, but the immunologic effects of the objective social isolation imposed by pandemic "shelter in place" (SIP) policies is unknown. We assessed the immunologic impact of SIP by relocating 21 adult male rhesus macaques from 2,000-m² field cage communities of 70 to 132 other macaques to 2 wk of individual housing in indoor shelters. SIP was associated with 30% to 50% reductions in all circulating immune cell populations (lymphocytes, monocytes, and granulocytes), down-regulation of Type I interferon (IFN) antiviral gene expression, and a relative up-regulation of CD16^- classical monocytes. These effects emerged within the first 48 h of SIP, persisted for at least 2 wk, and abated within 4 wk of return to social housing. A subsequent round of SIP in the presence of a novel juvenile macaque showed comparable reductions in circulating immune cell populations but reversal of Type I IFN reductions and classical monocyte increases observed during individual SIP. Analyses of lymph node tissues showed parallel up-regulation of Type I IFN genes and enhanced control of viral gene expression during juvenile-partnered SIP compared to isolated SIP. These results identify a significant adverse effect of SIP social isolation on antiviral immune regulation in both circulating immune cells and lymphoid tissues, and they suggest a potential behavioral strategy for ameliorating gene regulatory impacts (but not immune cell declines) by promoting prosocial engagement during SIP.

Antibiotic resistance during and beyond COVID-19

Antibiotics underpin the 'modern medicine' that has increased life expectancy, leading to societies with sizeable vulnerable elderly populations who have suffered disproportionately during the current COVID-19 pandemic. Governments have responded by shuttering economies, limiting social interactions and refocusing healthcare. There are implications for antibiotic resistance both during and after these events. During spring 2020, COVID-19-stressed ICUs relaxed stewardship, perhaps promoting resistance. Counterpoised to this, more citizens died at home and total hospital antibiotic use declined, reducing selection pressure. Restricted travel and social distancing potentially reduced community import and transmission of resistant bacteria, though hard data are lacking. The future depends on the vaccines now being deployed. Unequivocal vaccine success should allow a swift return to normality. Vaccine failure followed by extended and successful non-pharmaceutical suppression may lead to the same point, but only after some delay, and with indefinite travel restrictions; sustainability is doubtful. Alternatively, failure of vaccines and control measures may prompt acceptance that we must live with the virus, as in the prolonged 1889-94 'influenza' (or coronavirus OC43) pandemic. Vaccine failure scenarios, particularly those accepting 'learning to live with the virus', favour increased outpatient management of non-COVID-19 infections using oral and long t ½ antibiotics. Ultimately, all models-except those envisaging societal collapse-suggest that COVID-19 will be controlled and that hospitals will revert to pre-2020 patterns with a large backlog of non-COVID-19 patients awaiting treatment. Clearing this will increase workloads, stresses, nosocomial infections, antibiotic use and resistance. New antibiotics, including cefiderocol, are part of the answer.

The political economy of the COVID-19 pandemic

We argue that the policy response to the COVID-19 pandemic by all levels of government around the world is not consistent with recommendations from standard welfare economics. Thus, it is important to ask why such policies have been adopted. That opens the door to examining the political economy of the COVID-19 pandemic. This requires examining the incentives and information that confront policymakers and voters and the institutional environments that shape their incentives and information. This lead article frames questions addressed in the remainder of the symposium.

COVID-19 and the Political Economy of Mass Hysteria

In this article, we aim to develop a political economy of mass hysteria. Using the background of COVID-19, we study past mass hysteria. Negative information which is spread through mass media repetitively can affect public health negatively in the form of nocebo effects and mass hysteria. We argue that mass and digital media in connection with the state may have had adverse consequences during the COVID-19 crisis. The resulting collective hysteria may have contributed to policy errors by governments not in line with health recommendations. While mass hysteria can occur in societies with a minimal state, we show that there exist certain self-corrective mechanisms and limits to the harm inflicted, such as sacrosanct private property rights. However, mass hysteria can be exacerbated and self-reinforcing when the negative information comes from an authoritative source, when the media are politicized, and social networks make the negative information omnipresent. We conclude that the negative long-term effects of mass hysteria are exacerbated by the size of the state.

Leveraging epidemiological principles to evaluate Sweden's COVID-19 response

In the response to COVID-19, countries have implemented response strategies along a continuum of population- and venue-level specificity ranging from suppression to mitigation strategies. Suppression strategies generally include population-wide shelter-in-place mandates or lockdowns, closure of nonessential physical venues, travel bans, testing and contact tracing, and quarantines. Sweden followed a mitigation strategy focused on risk-tailored approaches to mitigate specific acquisition risks among the elderly, minimizing the disruption to education and the delivery of other health care services, and recommendations for social distancing to minimize the disease burden. To date, Sweden has reported higher case counts and attributable mortality than other Scandinavian countries and lower than other Northern European countries. However, there are several limitations with comparison given heterogeneity in testing strategies, suspected and confirmed case definitions, and assessment of attributable mortality. The decisions in Sweden also reflect social priorities such as equity being a foundational principle of Swedish social systems. Consistently, in-person education for those aged less than 16 years continued throughout. Notably, the mitigation strategy did not eliminate the inequitable impacts of COVID-19 cases and mortality in Sweden with higher-exposure and generally lower-income occupations being associated with higher risks intersecting with these communities often residing in more dense multigenerational households. From January 1 to November 15, there has been a 1.8% increase in all-cause mortality in 2020 compared with the average of 2015-2019, representing an excess of 14.3 deaths per 100,000 population. However, the final assessment of excess deaths in Sweden in 2020 including stratification by age and integration of secular trends can only be calculated in the coming years. In response to increasing cases in the fall of 2020, Sweden has continued to leverage business-oriented regulations and public-oriented guidelines for social distancing rather than police-enforced mandates. Ultimately, pandemics present no winners. Countries have implemented a range of different COVID-19 prevention and mitigation strategies responsive to their own priorities and legal systems including equity and the balancing of competing health priorities. Given these varied approaches, countries that pursued elimination, suppression, or mitigation strategies can collaboratively learn from both successes and challenges of the different strategies to inform COVID-19 and future pandemic responses.

Evaluating the impact of stay-at-home orders on the time to reach the peak burden of Covid-19 cases and deaths: does timing matter?

BACKGROUND

The economic, psychological, and social impact of pandemics and social distancing measures prompt the urgent need to determine the efficacy of non-pharmaceutical interventions (NPIs), especially those considered most stringent such as stay-at-home and self-isolation mandates. This study focuses specifically on the impact of stay-at-home orders, both nationally and internationally, on the control of COVID-19.

METHODS

We conducted an observational analysis from April to May 2020 and included both countries and US states with known stay-at-home orders. Our primary exposure was the time between the date of the first reported case of COVID-19 to an implemented stay-at-home mandate for each region. Our primary outcomes were the time from the first reported case to the highest number of daily cases and daily deaths. We conducted linear regression analyses, controlling for the case rate of the outbreak in each respective region.

RESULTS

For countries and US states, a longer period of time between the first reported case and stay-at-home mandates was associated with a longer time to reach both the peak daily case and death counts. The largest effect was among regions classified as the latest 10% to implement a mandate, which in the US, predicted an extra 35.3 days (95% CI: 18.2, 52.5) to the peak number of cases, and 38.3 days (95% CI: 23.6, 53.0) to the peak number of deaths.

CONCLUSIONS

Our study supports the association between the timing of stay-at-home orders and the time to peak case and death counts for both countries and US states. Regions in which mandates were implemented late experienced a prolonged duration to reaching both peak daily case and death counts.

National Institutes of Health social and behavioral research in response to the SARS-CoV2 Pandemic

The COVID-19 pandemic has been mitigated primarily using social and behavioral intervention strategies, and these strategies have social and economic impacts, as well as potential downstream health impacts that require further study. Digital and community-based interventions are being increasingly relied upon to address these health impacts and bridge the gap in health care access despite insufficient research of these interventions as a replacement for, not an adjunct to, in-person clinical care. As SARS-CoV-2 testing expands, research on encouraging uptake and appropriate interpretation of these test results is needed. All of these issues are disproportionately impacting underserved, vulnerable, and health disparities populations. This commentary describes the various initiatives of the National Institutes of Health to address these social, behavioral, economic, and health disparities impacts of the pandemic, the findings from which can improve our response to the current pandemic and prepare us better for future infectious disease outbreaks.

“FIQUE EM CASA”: A GESTÃO DE RISCOS EM CONTEXTOS DE INCERTEZA

Resumo Partindo do pressuposto de que há lacunas no conhecimento sobre o novo coronavírus, este ensaio versa sobre a gestão de riscos em situações de incerteza. Inicia-se situando a pandemia de SARS CoV-2 e as características que nos levam a afirmar que há zonas de incertezas a ele associadas. A seguir, introduz-se a noção de gerenciamento de riscos como preâmbulo para uma breve síntese das medidas governamentais adotadas para controle da epidemia. Nesse enquadre é problematizada a “dança das palavras,” focalizando as estratégias de distanciamento social, discussão que leva à comunicação sobre risco e suas implicações para a adesão às medidas de distanciamento social no enquadre das teorizações sobre percepção de risco. Conclui-se, propondo que a contribuição da Psicologia Social, nessas situações, requer duas habilidades: de um lado, a comunicação sobre riscos e, de outro, entender como essas informações são processadas e significadas em distintos segmentos sociais.

Predicting support for non-pharmaceutical interventions during infectious outbreaks: a four region analysis

Non-pharmaceutical interventions (NPIs) are an important public health tool for responding to infectious disease outbreaks, including pandemics. However, little is known about the individual characteristics associated with support for NPIs, or whether they are consistent across regions. This study draws on survey data from four regions--Hong Kong, Singapore, Taiwan, and the United States--collected following the Severe Acute Respiratory Syndrome (SARS) outbreak of 2002-03, and employs regression techniques to estimate predictors of NPI support. It finds that characteristics associated with NPI support vary widely by region, possibly because of cultural variation and prior experience, and that minority groups tend to be less supportive of NPIs when arrest is the consequence of noncompliance. Prior experience of face-mask usage also results in increased support for future usage, as well as other NPIs. Policymakers should be attentive to local preferences and to the application of compulsory interventions. It is speculated here that some public health interventions may serve as 'gateway' exposures to future public health interventions.

Behavioural response in educated young adults towards influenza A(H1N1)pdm09

The purpose of this paper was to determine how contact behaviour change influences the indoor transmission of influenza A(H1N1)pdm09 among school children. We incorporated transmission rate matrices constructed from questionnaire responses into an epidemiological model to simulate contact behaviour change during an influenza epidemic. We constructed a dose-response model describing the relationships between contact rate, viral load, and respiratory symptom scores using published experimental human infection data for A(H1N1)pdm09. Findings showed that that mean numbers of contacts were 5.66 ± 6.23 and 1.96 ± 2.76 d-1 in the 13-19 and 40-59 years age groups, respectively. We found that the basic reproduction number (R 0) was <1 during weekends in pandemic periods, implying that school closures or class suspensions are probably an effective social distancing policy to control pandemic influenza transmission. We conclude that human contact behaviour change is a potentially influential factor on influenza infection rates. For substantiation of this effect, we recommend a future study with more comprehensive control measures.

Supply of neuraminidase inhibitors related to reduced influenza A (H1N1) mortality during the 2009-2010 H1N1 pandemic: summary of an ecological study

When the influenza A (H1N1) pandemic spread across the globe from April 2009 to August 2010, many WHO Member States used antiviral drugs, specifically neuraminidase inhibitors (NAIs) oseltamivir and zanamivir, to treat influenza patients in critical condition. Antivirals have been found to be effective in reducing severity and duration of influenza illness, and likely reduce morbidity; however, it is unclear whether NAIs used during the pandemic reduced H1N1 mortality. To assess the association between antivirals and influenza mortality, at an ecologic level, country-level data on supply of oseltamivir and zanamivir were compared to laboratory-confirmed H1N1 deaths (per 100 000 people) from July 2009 to August 2010 in 42 WHO Member States. From this analysis, it was found that each 10% increase in kilograms of oseltamivir, per 100 000 people, was associated with a 1·6% reduction in H1N1 mortality over the pandemic period [relative rate (RR) = 0·84 per log increase in oseltamivir supply]. Each 10% increase in kilogram of active zanamivir, per 100 000, was associated with a 0·3% reduction in H1N1 mortality (RR = 0·97 per log increase). While limitations exist in the inference that can be drawn from an ecologic evaluation, this analysis offers evidence of a protective relationship between antiviral drug supply and influenza mortality and supports a role for influenza antiviral use in future pandemics. This article summarises the original study described previously, which can be accessed through the following citation: Miller PE, Rambachan A, Hubbard RJ, Li J, Meyer AE, et al. (2012) Supply of Neuraminidase Inhibitors Related to Reduced Influenza A (H1N1) Mortality during the 2009-2010 H1N1 Pandemic: An Ecological Study. PLoS ONE 7(9): e43491.

Screening for influenza A(H1N1)pdm09, Auckland International Airport, New Zealand

Entry screening for influenza A(H1N1)pdm09 at Auckland International Airport, New Zealand, detected 4 cases, which were later confirmed, among 456,518 passengers arriving April 27-June 22, 2009. On the basis of national influenza surveillance data, which suggest that ≈69 infected travelers passed through the airport, sensitivity for screening was only 5.8%.

Supply of neuraminidase inhibitors related to reduced influenza A (H1N1) mortality during the 2009-2010 H1N1 pandemic: an ecological study

BACKGROUND

The influenza A (H1N1) pandemic swept across the globe from April 2009 to August 2010 affecting millions. Many WHO Member States relied on antiviral drugs, specifically neuraminidase inhibitors (NAIs) oseltamivir and zanamivir, to treat influenza patients in critical condition. Such drugs have been found to be effective in reducing severity and duration of influenza illness, and likely reduced morbidity during the pandemic. However, it is less clear whether NAIs used during the pandemic reduced H1N1 mortality.

METHODS

Country-level data on supply of oseltamivir and zanamivir were used to predict H1N1 mortality (per 100,000 people) from July 2009 to August 2010 in forty-two WHO Member States. Poisson regression was used to model the association between NAI supply and H1N1 mortality, with adjustment for economic, demographic, and health-related confounders.

RESULTS

After adjustment for potential confounders, each 10% increase in kilograms of oseltamivir, per 100,000 people, was associated with a 1.6% reduction in H1N1 mortality over the pandemic period (relative rate (RR) = 0.84 per log increase in oseltamivir supply). While the supply of zanamivir was considerably less than that of oseltamivir in each Member State, each 10% increase in kilogram of active zanamivir, per 100,000, was associated with a 0.3% reduction in H1N1 mortality (RR = 0.97 per log increase).

CONCLUSION

While there are limitations to the ecologic nature of these data, this analysis offers evidence of a protective relationship between antiviral drug supply and influenza mortality and supports a role for influenza antiviral use in future pandemics.

A pandemic influenza modeling and visualization tool

The National Strategy for Pandemic Influenza outlines a plan for community response to a potential pandemic. In this outline, state and local communities are charged with enhancing their preparedness. In order to help public health officials better understand these charges, we have developed a visual analytics toolkit (PanViz) for analyzing the effect of decision measures implemented during a simulated pandemic influenza scenario. Spread vectors based on the point of origin and distance traveled over time are calculated and the factors of age distribution and population density are taken into effect. Healthcare officials are able to explore the effects of the pandemic on the population through a geographical spatiotemporal view, moving forward and backward through time and inserting decision points at various days to determine the impact. Linked statistical displays are also shown, providing county level summaries of data in terms of the number of sick, hospitalized and dead as a result of the outbreak. Currently, this tool has been deployed in Indiana State Department of Health planning and preparedness exercises, and as an educational tool for demonstrating the impact of social distancing strategies during the recent H1N1 (swine flu) outbreak.

Economic and social impact of influenza mitigation strategies by demographic class

BACKGROUND

We aim to determine the economic and social impact of typical interventions proposed by the public health officials and preventive behavioral changes adopted by the private citizens in the event of a "flu-like" epidemic.

METHOD

We apply an individual-based simulation model to the New River Valley area of Virginia for addressing this critical problem. The economic costs include not only the loss in productivity due to sickness but also the indirect cost incurred through disease avoidance and caring for dependents.

RESULTS

The results show that the most important factor responsible for preventing income loss is the modification of individual behavior; it drops the total income loss by 62% compared to the base case. The next most important factor is the closure of schools which reduces the total income loss by another 40%.

CONCLUSIONS

The preventive behavior of the private citizens is the most important factor in controlling the epidemic.

Inactivated split-virion seasonal influenza vaccine (Fluarix): a review of its use in the prevention of seasonal influenza in adults and the elderly

Fluarix is a trivalent, inactivated, split-virion influenza vaccine containing 15 microg haemagglutinin from each of the three influenza virus strains (including an H1N1 influenza A virus subtype, an H3N2 influenza A virus subtype and an influenza B virus) that are expected to be circulating in the up-coming influenza season. Fluarix is highly immunogenic in healthy adults and elderly, and exceeds the criteria that make it acceptable for licensure in various regions (including the US and Europe). In a large, phase III, placebo-controlled, double-blind trial conducted in the US (2004/2005) in subjects aged 18-64 years, postvaccination seroconversion rates against the H1N1, H3N2 and B antigens were 60-78% and respective postvaccination seroprotection rates were 97-99% in Fluarix recipients. Another phase III trial conducted in the US (2005/2006) established the noninferiority of Fluarix versus another trivalent inactivated influenza virus vaccine in subjects aged >or=18 years, including a subgroup of elderly subjects. In annual European registration trials, Fluarix has consistently exceeded the immunogenicity criteria set by the EU Committee for Medicinal Products for Human Use for adults and the elderly. Fluarix demonstrated immunogenicity in small, open-label studies in at-risk subjects. During a year when the vaccine was well matched to the circulating strain, Fluarix demonstrated efficacy against culture-confirmed influenza A and/or B in a placebo-controlled trial in adults aged 18-64 years. In addition, Fluarix vaccination of pregnant women demonstrated efficacy in reducing the rate of laboratory-confirmed influenza in the infants and reducing febrile respiratory illnesses in the mothers and their new-born infants in a randomized trial. Fluarix was generally well tolerated in adults and the elderly in well designed clinical trials and in the annual European registration trials, with most local and general adverse events being transient and mild to moderate in intensity. The most common adverse reactions in recipients of Fluarix were pain, redness or swelling at the injection site, muscle aches, fatigue, headache and arthralgia. In conclusion, Fluarix is an important means of decreasing the impact of seasonal influenza viruses on adults and the elderly.

Knowledge and adoption of community mitigation efforts in Mexico during the 2009 H1N1 pandemic

BACKGROUND

The public's ability and willingness to adopt community mitigation efforts during a pandemic are debated in the literature.

PURPOSE

Awareness and adoption of community mitigation efforts in Mexico during the 2009 pandemic influenza A (H1N1) (pH1N1) outbreak were measured to evaluate if the population received, understood, and acted on public health messages.

METHODS

A cross-sectional representative household survey in Mexico City; San Luis Potosi (high case ratio); and Queretaro (low case ratio) was conducted in May and June 2009. Accounting for the complex survey design, percentages and 95% CI for answers to all questions were generated and compared based on living inside or outside Mexico City, high versus low prevalence of infection in the community, and perceived severity and knowledge of the virus.

RESULTS

Greater than 90% of respondents received community mitigation messages and adopted one or more community mitigation efforts. There were few differences among cities. Respondents reported high cost of masks, soaps, and gels as barriers to community mitigation-effort adoption. Nearly one fifth of respondents, disproportionally from the lower socioeconomic tertile, found some messages confusing. Half of all households reported a negative economic impact resulting from the outbreak.

CONCLUSIONS

Mexico's community mitigation campaign reached the majority of the population in three surveyed cities. Confusion regarding messages and economic barriers to community mitigation-effort adoption were sometimes reported.

Influence of country of study on student responsiveness to the H1N1 pandemic

Objectives

University students, both travelling abroad on holiday or exchange students entering a country, can serve as mobile carriers of infectious diseases during a pandemic, and thus require special attention when considering preventive measures. The objectives of this study were to evaluate student compliance and opinions on preventive measures of a university before and during an H1N1 influenza pandemic, and to explore environmental and behavioural factors that might contribute towards compliance.

Study design

Cross-sectional, self-administered questionnaire.

Methods

Local and foreign students attending an international summer school programme were invited to participate in a self-administered survey.

Results

Respondents complied with most of the preventive measures, excluding website viewing and mask wearing. Significant differences in compliance and perceived necessity were found amongst students from Singapore, Hong Kong and the USA. Singaporean students were significantly more likely to comply with all measures and consume antiviral medication in response to the pandemic than students studying in the US.

Conclusions

Students’ responses towards university pandemic measures were largely positive, but sensitivity towards these measures varied between groups by country of study. This should be considered in further comparative studies.

Association between school closure and subsequent absenteeism during a seasonal influenza epidemic

BACKGROUND

Mathematical models suggest that social distancing measures, such as school closures, may mitigate community transmission during an influenza pandemic. Because closures are disruptive to schools and families, they are rarely employed during seasonal influenza outbreaks. A rare circumstance enabled us to examine the association between school closure and absenteeism during a seasonal influenza outbreak when half of King County, Washington public schools closed for a winter recess 19-23 February 2007, while half remained open for all or part of the week.

METHODS

Using absenteeism as a proxy for influenza activity, we tested the hypothesis that schools on break would experience lower rates of post-break absenteeism than schools remaining open. We conducted daily retrospective and prospective surveillance from 5 February-9 March 2007 in schools on break (n = 256) and in session (n = 205). We use generalized estimating equations with Poisson distribution to evaluate whether mean absenteeism after the break differed between schools on break and those in session, adjusting for baseline absenteeism and repeated measurements by schools over time.

RESULTS

Results indicate no difference in post-break absenteeism in schools on break compared with schools that remained in session (relative risk = 1.07 [95% confidence interval = 0.96-1.20]). This result held in elementary schools (1.00 [0.91-1.10]), where absenteeism patterns are thought to be most representative of community influenza activity.

CONCLUSION

We did not find that school closure during a seasonal influenza outbreak reduced subsequent absenteeism. However, limitations in this "natural experiment" hampered our ability to detect a benefit if one truly was present.

Prophylaxis of Healthcare Workers in an Influenza Pandemic

The threat of an imminent influenza pandemic has galvanized global efforts to identify effective preparedness strategies and consider securing health resources. As the nations prepare to meet this threat, public health interventions are being carefully gauged within the context of influenza epidemiology, populations, and healthcare systems. A pandemic will place enormous demands on healthcare systems that include at the center of planning efforts the protection of healthcare workers. During an influenza pandemic, healthcare workers will be on the front lines delivering care to patients and preventing further spread of the disease. Protecting these workers from acquiring or transmitting infection in the hospital ward and outside the workplace is critical to containing a pandemic and limiting morbidity and mortality of the population. Several approaches to protecting healthcare workers include vaccination, antiviral 10.1007/978-0-387-78665-0_6443, use of personal protective equipment, and adherence to other infection control practices. In the absence of vaccination, application of antiviral drugs has been rationalized as the first-line defense against the 10.1007/978-0-387-78665-0_6288. While the treatment of ill individuals is top priority in most national contingency plans, the use of drugs as prophylaxis has been debatable. This chapter attempts to highlight the importance of a competent healthcare system in response to an influenza pandemic, and presents the conflicting issues that are surrounding an antiviral prophylaxis strategy. An overview of potential benefits and limitations, logistical constraints, and clinical and epidemiological consequences of healthcare worker prophylaxis is also provided.

A primer on strategies for prevention and control of seasonal and pandemic influenza

The United States has made considerable progress in pandemic preparedness. Limited attention, however, has been given to the challenges faced by populations that will be at increased risk of the consequences of the pandemic, including challenges caused by societal, economic, and health-related factors. This supplement to the American Journal of Public Health focuses on the challenges faced by at-risk and vulnerable populations in preparing for and responding to an influenza pandemic. Here, we provide background information for subsequent articles throughout the supplement. We summarize (1) seasonal influenza epidemiology, transmission, clinical illness, diagnosis, vaccines, and antiviral medications; (2) H5N1 avian influenza; and (3) pandemic influenza vaccines, antiviral medications, and nonpharmaceutical interventions.

Closure of schools during an influenza pandemic

In response to WHO raising the influenza pandemic alert level from phase five to phase six, health officials around the world are carefully reviewing pandemic mitigation protocols. School closure (also called class dismissal in North America) is a non-pharmaceutical intervention that is commonly suggested for mitigating influenza pandemics. Health officials taking the decision to close schools must weigh the potential health benefits of reducing transmission and thus case numbers against high economic and social costs, difficult ethical issues, and the possible disruption of key services such as health care. Also, if schools are expected to close as a deliberate policy option, or just because of high levels of staff absenteeism, it is important to plan to mitigate the negative features of closure. In this context, there is still debate about if, when, and how school closure policy should be used. In this Review, we take a multidisciplinary and holistic perspective and review the multiple aspects of school closure as a public health policy. Implications for the mitigation of the swine-origin influenza A H1N1 pandemic are also discussed.

Antiviral resistance during pandemic influenza: implications for stockpiling and drug use

Background

The anticipated extent of antiviral use during an influenza pandemic can have adverse consequences for the development of drug resistance and rationing of limited stockpiles. The strategic use of drugs is therefore a major public health concern in planning for effective pandemic responses.

Methods

We employed a mathematical model that includes both sensitive and resistant strains of a virus with pandemic potential, and applies antiviral drugs for treatment of clinical infections. Using estimated parameters in the published literature, the model was simulated for various sizes of stockpiles to evaluate the outcome of different antiviral strategies.

Results

We demonstrated that the emergence of highly transmissible resistant strains has no significant impact on the use of available stockpiles if treatment is maintained at low levels or the reproduction number of the sensitive strain is sufficiently high. However, moderate to high treatment levels can result in a more rapid depletion of stockpiles, leading to run-out, by promoting wide-spread drug resistance. We applied an antiviral strategy that delays the onset of aggressive treatment for a certain amount of time after the onset of the outbreak. Our results show that if high treatment levels are enforced too early during the outbreak, a second wave of infections can potentially occur with a substantially larger magnitude. However, a timely implementation of wide-scale treatment can prevent resistance spread in the population, and minimize the final size of the pandemic.

Conclusion

Our results reveal that conservative treatment levels during the early stages of the outbreak, followed by a timely increase in the scale of drug-use, will offer an effective strategy to manage drug resistance in the population and avoid run-out. For a 1918-like strain, the findings suggest that pandemic plans should consider stockpiling antiviral drugs to cover at least 20% of the population.

Household responses to school closure resulting from outbreak of influenza B, North Carolina

School closure is a proposed strategy for reducing influenza transmission during a pandemic. Few studies have assessed how families respond to closures, or whether other interactions during closure could reduce this strategy's effect. Questionnaires were administered to 220 households (438 adults and 355 children) with school-age children in a North Carolina county during an influenza B virus outbreak that resulted in school closure. Closure was considered appropriate by 201 (91%) households. No adults missed work to solely provide childcare, and only 22 (10%) households required special childcare arrangements; 2 households incurred additional costs. Eighty-nine percent of children visited at least 1 public location during the closure despite county recommendations to avoid large gatherings. Although behavior and attitudes might differ during a pandemic, these results suggest short-term closure did not cause substantial hardship for parents. Pandemic planning guidance should address the potential for transmission in public areas during school closure.

Public response to community mitigation measures for pandemic influenza

We report the results of a national survey conducted to help public health officials understand the public's response to community mitigation interventions for a severe outbreak of pandemic influenza. Survey results suggest that if community mitigation measures are instituted, most respondents would comply with recommendations but would be challenged to do so if their income or job were severely compromised. The results also indicate that community mitigation measures could cause problems for persons with lower incomes and for racial and ethnic minorities. Twenty-four percent of respondents said that they would not have anyone available to take care of them if they became sick with pandemic influenza. Given these results, planning and public engagement will be needed to encourage the public to be prepared.

Healthcare epidemiology: the current status of planning for pandemic influenza and implications for health care planning in the United States

The United States needs to be better prepared for a large-scale medical catastrophe, be it a natural disaster, a bioterrorism act, or a pandemic. There are substantial planning efforts now devoted to responding to an influenza pandemic. Here, we review these efforts and identify some harsh realities: (1) the US health care system is private, competitive, broke, and at capacity, so that any demand for surge cannot be met with existing economic resources, hospital beds, manpower, or supplies; (2) the emphasis placed on the development and rapid production of an effective vaccine is excellent, but the effort is underfunded to meet global demand; (3) and the Centers for Disease Control and Prevention's community mitigation measures, such as the use nonpharmacological and social interventions (e.g., use of face masks or respirators, social distancing, and closure of schools), lack validation and could have substantial indirect and unintended consequences. Finally, international collaborations are essential for disease surveillance and to assure investigator access to influenza strains, equitable vaccine distribution, and availability of critical supplies from offshore sources.

Non-pharmaceutical public health interventions for pandemic influenza: an evaluation of the evidence base

BACKGROUND

In an influenza pandemic, the benefit of vaccines and antiviral medications will be constrained by limitations on supplies and effectiveness. Non-pharmaceutical public health interventions will therefore be vital in curtailing disease spread. However, the most comprehensive assessments of the literature to date recognize the generally poor quality of evidence on which to base non-pharmaceutical pandemic planning decisions. In light of the need to prepare for a possible pandemic despite concerns about the poor quality of the literature, combining available evidence with expert opinion about the relative merits of non-pharmaceutical interventions for pandemic influenza may lead to a more informed and widely accepted set of recommendations. We evaluated the evidence base for non-pharmaceutical public health interventions. Then, based on the collective evidence, we identified a set of recommendations for and against interventions that are specific to both the setting in which an intervention may be used and the pandemic phase, and which can be used by policymakers to prepare for a pandemic until scientific evidence can definitively respond to planners' needs.

METHODS

Building on reviews of past pandemics and recent historical inquiries, we evaluated the relative merits of non-pharmaceutical interventions by combining available evidence from the literature with qualitative and quantitative expert opinion. Specifically, we reviewed the recent scientific literature regarding the prevention of human-to-human transmission of pandemic influenza, convened a meeting of experts from multiple disciplines, and elicited expert recommendation about the use of non-pharmaceutical public health interventions in a variety of settings (healthcare facilities; community-based institutions; private households) and pandemic phases (no pandemic; no US pandemic; early localized US pandemic; advanced US pandemic).

RESULTS

The literature contained a dearth of evidence on the efficacy or effectiveness of most non-pharmaceutical interventions for influenza. In an effort to inform decision-making in the absence of strong scientific evidence, the experts ultimately endorsed hand hygiene and respiratory etiquette, surveillance and case reporting, and rapid viral diagnosis in all settings and during all pandemic phases. They also encouraged patient and provider use of masks and other personal protective equipment as well as voluntary self-isolation of patients during all pandemic phases. Other non-pharmaceutical interventions including mask-use and other personal protective equipment for the general public, school and workplace closures early in an epidemic, and mandatory travel restrictions were rejected as likely to be ineffective, infeasible, or unacceptable to the public.

CONCLUSION

The demand for scientific evidence on non-pharmaceutical public health interventions for influenza is pervasive, and present policy recommendations must rely heavily on expert judgment. In the absence of a definitive science base, our assessment of the evidence identified areas for further investigation as well as non-pharmaceutical public health interventions that experts believe are likely to be beneficial, feasible and widely acceptable in an influenza pandemic.

Community engagement: leadership tool for catastrophic health events

Disasters and epidemics are immense and shocking disturbances that require the judgments and efforts of large numbers of people, not simply those who serve in an official capacity. This article reviews the Working Group on Community Engagement in Health Emergency Planning's recommendations to government decision makers on why and how to catalyze the civic infrastructure for an extreme health event. Community engagement--defined here as structured dialogue, joint problem solving, and collaborative action among formal authorities, citizens at-large, and local opinion leaders around a pressing public matter--can augment officials' abilities to govern in a crisis, improve application of communally held resources in a disaster or epidemic, and mitigate community wide losses. The case of limited medical options in an influenza pandemic serves to demonstrate the civic infrastructure's preparedness, response, and recovery capabilities and to illustrate how community engagement can improve pandemic contingency planning.