What is the Hazard?
A pandemic is a global infectious disease outbreak. For biological threats, an influenza pandemic presents the highest public health disaster risk to New York City, with the potential for high morbidity and mortality, massive strain on the healthcare system, profound economic impacts, and significant disruptions to daily life for all New Yorkers.
Influenza viruses, as well as certain other respiratory viruses, are readily transmitted in a population, can mutate frequently so that most of the population has little if any immunity to new strains, and cause severe illness and death. Recently, a novel strain of H7N9 influenza and a novel coronavirus, the Middle Eastern Respiratory Syndrome coronavirus, have emerged; both viruses have been associated with high fatality rates. Pandemic influenzas typically have two or three waves, or “peaks,” of infection lasting 8 to 12 weeks in duration while other respiratory pandemics have less defined characteristics.
Contributors to the Public Health Severity of a Hazard, by Weight
|Severe injuries and an increase in illness||15.5%|
|Risk of an associated disease outbreak||13.4%|
|Disruption to the potable water supply||12.1%|
|Increase in harmful or life-threatening toxic exposures and environmental contamination||10.0%|
|Loss of utility-provided power||9.7%|
|Diminished capacity of the healthcare system||9.2%|
|Disruption of communication systems||7.5%|
Pandemic Influenza Morbidity and MortalityTo understand the potential impact on New Yorkers and the healthcare system, DOHMH uses two pandemic influenza scenarios to estimate the burden of disease, a more likely mild/moderate scenario and a severe scenario based on the 1918 influenza pandemic
Mild/Moderate Pandemic ScenarioA mild/moderate pandemic wave of a novel influenza hits New York City over a 10-week period. An estimated 1.5 million New Yorkers may become ill and approximately 500 die from the illness citywide. There is above average strain on the healthcare system. Hospital emergency department visits and outpatient services are higher than normal. This pandemic scenario resembles the 1957 influenza season and 2009 H1N1 pandemic. For a mild/moderate pandemic, our general assumptions include:
- An attack rate of 18% and a case fatality rate of .03%.
- Susceptibility to the pandemic influenza subtype will be nearly
- City agencies, healthcare facilities and businesses will experience increased worker absenteeism and increased demand for medical and social services.
- Surge of healthcare staff will be needed to provide both outpatient and inpatient care staff in emergency departments. Primary care physicians, emergency medicine physicians, and pediatricians especially could become
- Increased infection control measures may be recommended beyond those normally recommended for seasonal
- Spot shortages of medications and supplies associated with infection control (e.g., PPE).
- The anticipated time from identification of a pandemic strain to vaccine manufacture ranges from 4 to 6 months, with early doses most likely to be limited to federally identified priority groups (e.g.: active military, pregnant women, children).
Severe Pandemic ScenarioA severe pandemic wave of novel influenza hits New York City over a 10-week period. The attack rate is 33% with a case fatality rate of 2.5% (similar to the pandemic of 1918). An estimated 2.8 million New Yorkers may become ill and approximately 71,000 die from the illness citywide. Morbidity and mortality will be high during this event. There will be great demand on the New York City 911 system to respond to medical calls and high rates of staff absence across the healthcare system will further exacerbate this issue. Hospital capacity within the city is heavily impacted, especially during peak demand. Table 2. Potential NYC Pandemic Influenza Impact Severe Scenario Assumes an attack rate of 33% (similar to 1918) and case fatality rate of 2.5% (same as 1918). These estimates are based on scenarios that are unmitigated, meaning that they do not account for public health interventions that would likely be implemented during a pandemic.
Potential NYC Pandemic Influenza Impact Severe Scenario
|Illness||Outpatient Medical Care||Hospitalization||ICU Care||Deaths|
- Community mitigation measures (e.g. school closures, cancellation of public events, public to stay home) may be recommended by CDC.
- Extreme strain on City and other critical (e.g. Con Ed, etc.) agencies to maintain critical functions due to excessive and prolonged staff absenteeism.
- Increased demand on health and human services by both the ill and the “worried well” seeking information.
- Increased news coverage and spread of false information may lead to increased stress among the population.
- Increased demand for information by the public and healthcare providers.
- Shortages of beds (especially in Intensive Care Units and ventilators), staffing, and supplies within the healthcare system.
- Potential for antiviral and other medical supply shortages.
- Public more unwilling or unable to leave home due to illness, self-imposed home isolation, and/or public health requests to avoid going into public places.
Contributors to Estimating the Probability of a Public Health Hazard, by Weight
|Changes in the environment or threat landscape that makes it more likely to occur||38.0%|
|Forecast models and academic or actuarial studies||23.4%|
|An increasing frequency of similar events||23.2%|
|The number of reported occurences||15.3%|
Respiratory Viruses with Pandemic Potential, since 1900