Active Learning Guide: Seasonal and Pandemic Influenza (Fall 2024)

Active Learning Guide – Seasonal Influenza and Pandemic Influenza Fall 24 N4530 Community Health Nursing This week you will be looking at seasonal flu that we see every year about this time until about March in this area of the world. Flu is common and many of us have had the flu, yet it remains a s...

Active Learning Guide – Seasonal Influenza and Pandemic Influenza Fall 24 N4530 Community Health Nursing This week you will be looking at seasonal flu that we see every year about this time until about March in this area of the world. Flu is common and many of us have had the flu, yet it remains a significant issue for public health. You will also explore pandemic influenza – what happens to create an influenza pandemic. The textbook will be your starting point but most of the information will come from the links provided. Outcomes: Describe the natural life history and epidemiology of influenza and how seasonal and pandemic flu differ Describe the types of influenza and the ways the virus changes; the difference in drift and shifts in the virus Explain how the reproductive number (R0) is used to determine the possible impact of seasonal influenza each year and during pandemics Know the groups most at risk from influenza and preventive measures needed Reading: Nies & McEwen Ch. 26 and CDC Pinkbook Ch. 12 Influenza (this chapter has very good “study boxes” https://www.cdc.gov/pinkbook/hcp/table-of-contents/chapter-12-influenza.html and CDC Flu page https://www.cdc.gov/flu/index.html 1. What is the case definition for influenza (the flu)? Fever greater than or equal to 100 (37.8 C) PLUS Either a cough or a sore throat without a known diagnosis. Persons who meet this case definition are candidates for influenza diagnostic testing and treatment. 2. When is flu season in the US? Flu season in the United States typically begins in the fall and lasts through the spring, with activity peaking between December and February South America? Flu season in South America is typically from April to September, with peaks in June to August. However, the season can sometimes extend into October or November. Influenza means “influence of the stars” noting its seasonal history. 3. What is the natural life history of flu? Influenza is an infectious viral illness. The name "influenza" originated in 15th century Italy, from an epidemic attributed to "influence of the stars." The first documented pandemic, or worldwide epidemic, that clearly fits the  description of influenza was in 1580. At least four pandemics of influenza occurred in the 19th century, three in the 20th century, and one thus far in the 21st century. The pandemic of "Spanish" influenza in 1918–1919 caused an estimated 21 million deaths worldwide. Wilson Smith, Christopher Andrewes, and Patrick Laidlaw isolated influenza A virus in ferrets in 1933, and Thomas Francis Jr. isolated influenza B virus in 1936. Also in 1936, Macfarlane Burnet discovered that influenza virus could be grown in embryonated hens' eggs. This led to the study of the virus's characteristics and the development and use of inactivated vaccines in the late 1930s and 1940s. The protective efficacy of these inactivated vaccines was demonstrated in the 1950s. The first live, attenuated influenza vaccine was licensed in 2003. A non-live, recombinant influenza virus vaccine not requiring isolation or growth in hen's eggs was licensed in 2013. 4. How is influenza transmitted? Following respiratory transmission, the virus attaches to and penetrates respiratory epithelial cells in the trachea and bronchi. Viral replication occurs, which results in the destruction of the host cell. Regeneration of epithelium takes about 3 to 4 weeks. Viremia, or presence of virus in the blood, has rarely been documented. Virus is shed in respiratory secretions for 5 to 10 days, with a peak of 1 to 3 days following illness onset. Influenza is primarily transmitted from person to person via large, virus-laden droplets (more than 5 microns in diameter) that are generated when infected persons cough or sneeze. These large droplets can then settle on the mucosal surfaces of the upper respiratory tracts of susceptible persons who are within six feet of infected persons. Aerosol transmission of small droplets may also transmit influenza. Transmission may occur through direct or indirect contact with respiratory secretions, such as when touching surfaces contaminated with influenza virus and then touching the eyes, nose, or mouth. 5. What is the incubation period? The incubation period for influenza is usually 2 days but can vary from 1 to 4 days. Influenza illness can range from asymptomatic to severe infection. On average, about 8% of the U.S. population gets sick from influenza each season (range between 3% and 11%). 6. When does the communicable period begin and end? Adults can transmit influenza from the day before symptom onset to approximately 5 to 7 days after symptoms begin. Children can transmit influenza to others for 10 or more days after symptoms begin. 7. Time to resolution? Recovery is rapid; fever usually resolves within 3 to 4 days and other symptoms within approximately 7 days. Some patients may have lingering asthenia (lack of strength or energy) for several weeks. Note that children can be contagious sooner and longer. https://www.cdc.gov/flu/signs-symptoms/?CDC_AAref_Val=https://www.cdc.gov/flu/ symptoms/symptoms.htm 8. The usual attack rate is approximately 10%, meaning what? 10% of the people exposed to the influenza virus will develop the the illness. The attack rate for flu is variable, what would likely affect this rate? 9. What are the common symptoms of the flu? Flu can cause mild to severe illness, and at times can lead to death. Flu symptoms usually come on suddenly. People who have flu often feel some or all of these signs and symptoms: ◦ fever* or feeling feverish/chills ◦ cough ◦ sore throat ◦ runny or stuffy nose ◦ muscle or body aches ◦ headaches ◦ fatigue (tiredness) ◦ some people may have vomiting and diarrhea, though this is more common in children than adults. https://www.cdc.gov/flu/index.html Compare the onset of symptoms of the flu with the onset of cold symptoms. Signs and Symptoms Cold Flu Symptoms onset Gradual Abrupt Fever Rare Common; lasts 3-4 days Aches Slight Common; often severe Chills Uncommon Fairly common Fatigue, Weakness Sometimes Usual Sneezing Common Sometimes Chest discomfort, cough Mild to moderate Common; can be severe Stuffy nose Common Sometimes Sore throat Common Sometimes  Headache Rare Common 10.What are symptoms that would need to be referred for medical evaluation? In children ◦ Fast breathing or trouble breathing ◦ Bluish lips or face ◦ Ribs pulling in with each breath ◦ Chest pain ◦ Severe muscle pain (child refuses to walk) ◦ Dehydration (no urine for 8 hours, dry mouth, no tears when crying) ◦ Not alert or interacting when awake ◦ Seizures ◦ Fever above 104 degrees Fahrenheit that is not controlled by fever- reducing medicine ◦ In children younger than 12 weeks, any fever ◦ Fever or cough that improve but then return or worsen ◦ Worsening of chronic medical conditions In adults ◦ Difficulty breathing or shortness of breath ◦ Persistent pain or pressure in the chest or abdomen ◦ Persistent dizziness, confusion, inability to arouse ◦ Seizures ◦ Not urinating ◦ Severe muscle pain ◦ Severe weakness or unsteadiness ◦ Fever or cough that improve but then return or worsen ◦ Worsening of chronic medical conditions 11.What is the most common complication of the flu?  Most people who get flu will recover in a few days to less than two weeks, but some people will develop complications (such as pneumonia) as a result of flu, some of which can be life-threatening and result in death. Sinus and ear infections are examples of moderate complications from flu, while pneumonia is a serious flu complication that can result from either flu virus infection alone or from co-infection of flu virus and bacteria. Other possible serious complications triggered by flu can include inflammation of the heart (myocarditis), brain (encephalitis) or muscle tissues (myositis, rhabdomyolysis), and multi-organ failure (for example, respiratory and kidney failure). Flu virus infection of the respiratory tract can trigger an extreme inflammatory response in the body and can lead to sepsis, the body's life- threatening response to infection. Flu also can make chronic medical problems worse. For example, people with asthma may experience asthma attacks while they have flu, and people with chronic heart disease may experience a worsening of this condition triggered by flu. 12. What age groups are at higher risk of complications? Anyone can get sick with flu, even healthy people, and serious problems related to flu can happen to anyone at any age, but some people are at higher risk of developing serious flu-related complications if they get sick. This includes people 65 years and older, people of any age with certain chronic medical conditions (such as asthma, diabetes, or heart disease), pregnant people and children younger than 5 years, but especially those younger than 2 years old. Review testing for influenza on the For Professionals tab on the CDC flu page. https://www.cdc.gov/flu/hcp/testing-methods/clinician_guidance_ridt.html? CDC_AAref_Val=https://www.cdc.gov/flu/professionals/diagnosis/ clinician_guidance_ridt.htm The influenza virus is an orthomyxovirus and there are 3 types – A, B, and C. They are differentiated by the type of protein in the nucleus, specifically antigenic properties. 13.Which of these has subtypes? Influenza is a single-stranded, helically shaped, RNA virus of the orthomyxovirus family. Three types of influenza virus are known to affect humans: A, B, and C. Type A influenza has subtypes determined by the surface antigens hemagglutinin (HA) and neuraminidase (NA). There are 18 different H subtypes and 11 different N subtypes. Eight H subtypes (H1, H2, H3, H5, H6, H7, H9, H10) and six N subtypes (N1, N2, N6, N7, N8, and N9) have been detected in humans. Type B influenza is classified into two lineages: B/Yamagata and B/Victoria. Infection with influenza viruses can be asymptomatic or result in disease that ranges from mild to severe. Influenza B more commonly affects children. Influenza C is rarely reported as a cause of human illness, probably because  most cases are subclinical. Influenza C has not been associated with epidemic disease. Which one also affects animals? Antigenic shifts are probably due to genetic recombination (an exchange of a gene segment) between influenza A viruses that affect humans and/or animals. Influenza A viruses may infect both humans and some animals. Examples of animals include, but are not limited to, wild birds, poultry, pigs, horses, mink, and ferrets. There is no chronic carrier state. Type A virus is defined by glycoproteins – hemagglutinin (H) and neuraminidase (N) surface antigens on the virus. 14.During viral replication, which of these attaches the virus to cells? Hemagglutinin (H) attaches the virus to cells. The H protein performs as a key, that can attach to specific receptors on the surface of the host cells. These receptors are sialic acid-containing molecules that are found on the surface of the respiratory cells. This strategy of binding is critical for the virus to gain access into the cell. 15.Which one helps the virus penetrate the cell? Neuraminidase (N) helps the virus to penetrate the cell. Neuraminidase is a hydrolase enzyme (it breaks down specific chemical bonds. Particularly in the case of the influenza virus, N performs and cleave sialic acid molecules. This cleaving performance enables the virus to detach from the host cell, after the virus has been injected into the genetic material into the cell, enabling the discharge of newly formed virus fragments to infect/affect other cells. This will help you understand how the antivirals used for influenza work. Naming influenza viruses – In this order: Type A or B, geographic location where the virus was first isolated, strain number, year virus was first isolated, and the virus subtype combination of H and N antigens. Here is an example from fda.gov page with package insert of vaccines. 16.Why do the B Type viruses not have H and N designations? B type influenza viruses do not have H and N designations because , they exhibit significantly less genetic variation compared to type A influenza virusesmeaning their surface proteins (hemagglutinin - H and neuraminidase - N) do not change as rapidly, so they are not classified by subtype like the more variable type A viruses; instead, B type viruses are further categorized into lineages like B/Yamagata and B/Victoria.  https://www.fda.gov/vaccines- blood-biologics/vaccines/fluzone-quadrivalent-fluzone-high-dose-quadrivalent- fluzone-intradermal-quadrivalent-fluzone Seasonal – caused by drifts in the circulating influenza viruses. 17.What is the burden of disease for seasonal flu? The burden of flu disease in the United States can vary widely and is determined by a number of factors including the characteristics of circulating viruses, the timing of the season, how well flu vaccine is working to protect against illness, and how many people got vaccinated. While the burden of flu can vary, each year flu places a substantial burden on the health of people in the United States each year. How many cases per year in the US? CDC estimates that flu has resulted in 9.3 million – 41 million illnesses 18. Hospitalizations? 100,000 – 710,000 hospitalizations. Deaths? 4,900 – 51,000 deaths annually between 2010 and 2023. https://www.cdc.gov/flu-burden/php/about/index.html?CDC_AAref_Val=https:// www.cdc.gov/flu/about/burden/index.html Influenza remains a leading cause of death (see CDC Wonder, 15 Leading Causes of Death) in the US so it is important for nurses to educate the public on preventative measures including vaccination. https://www.cdc.gov/flu/index.htm 19.Epidemiologists will often calculate the R0 (reproductive number, pronounced R naught) to determine what about an infectious disease? The expected number of new infections caused by each infected person in a fully susceptible population and in the absence of interventions. 20.What is the RO of seasonal flu? Between 0.9 and 2.1. Measles? 12-18, which means that each person with measles would, on average, infect 12-18 other people in a totally susceptible population. Covid-19? Between 1.4 and 2.4. 21. What happens to the spread of disease if the R0 is less than 1?  If R0 is less than 1, the disease will die out in a population, because on average an infectious person will transmit to fewer than one other susceptible person. Greater than 1? On the other hand, if R0 is greater than 1, the disease will spread. 22. https://sph.umich.edu/pursuit/2020posts/how-scientists-quantify- outbreaks.html Look at the article from the University of Michigan School of Public Health, which disease listed was the most contagious? On the CDC flu page go to the Professionals tab https://www.cdc.gov/flu/index.html and to Ch. 12 in the Pink Book https://www.cdc.gov/pinkbook/hcp/table-of- contents/chapter-12-influenza.html Review the sections on vaccine recommendations from the ACIP. 23.What are the types of vaccines available for influenza? Three types of influenza vaccine are available in the United States: inactivated influenza vaccine (IIV); live, attenuated influenza vaccine (LAIV); and recombinant influenza vaccine (RIV). Trivalent vaccine contains three inactivated viruses: type A(H1N1), type A(H3N2), and type B. Quadrivalent influenza vaccines were first introduced during the 2013–2014 season. They contain the same antigens as trivalent vaccines, with an additional type B strain. 24.What is the difference between a trivalent vaccine and a quadrivalent vaccine? Trivalent vaccine contains three inactivated viruses: type A(H1N1), type A(H3N2), and type B. Quadrivalent influenza vaccines were first introduced during the 2013–2014 season. They contain the same antigens as trivalent vaccines, with an additional type B strain. 25. Who is recommended to receive a flu vaccine each year? The CDC recommends that get a flu vaccine every year, with some rare exceptions 26. What recommendations are there for those over 65 for the flu vaccine? For individuals over 65, the CDC recommends getting, a high-dose inactivated flu vaccine, a recombinant flu vaccine, or an adjuvanted inactivated flu vaccineas these are considered more effective than standard- dose flu vaccines for this age group; essentially, they should prioritize "higher dose" flu vaccines over regular ones. For children? According to the CDC, all children 6 months and older should receive an annual flu vaccine, with rare exceptions; this means even healthy children should get vaccinated every year.  Pregnant women? According to the CDC and most medical professionals, pregnant women should get the flu vaccine during any trimester of their pregnancy, as it is considered safe and highly recommended to protect both the mother and baby from potential complications of the flu; the preferred method is the flu shot (inactivated vaccine) and not the nasal spray vaccine (LAIV) which is not recommended for pregnant women. Those who are immune compromised? For those who are immunocompromised, the recommendation is to receive an annual influenza vaccine, specifically the inactivated (killed) version, and to avoid the live attenuated influenza vaccine (nasal spray) as it could be harmful to their weakened immune system; consult with your healthcare provider to determine the best flu vaccine option based on your specific condition and immune status. For uncomplicated care of the person ill with the flu, have them stay home, consider antivirals, rest, plenty of fluids, and symptom relief. 27.Who is recommended to consider the use of antiviral medication to treat influenza? According to the CDC, people considered at high risk of serious influenza complications, such as, older adults (65 and older), young children (especially under 2 years old), pregnant women, individuals with chronic medical conditions like asthma, heart disease, diabetes, and those hospitalized with the flu, should consider taking antiviral medication to treat influenza. 28.How do these medications work? Antiviral medications for influenza are typically recommended for people considered at high risk of developing serious complications from the flu, including the elderly, individuals with chronic health conditions like asthma, heart disease, diabetes, pregnant women, and people with compromised immune systems; these medications work best when taken within the first 48 hours of symptoms appearing by inhibiting the virus's ability to replicate and spread within the body, effectively shortening the duration of the illness and lessening its severity 29.What is the timeframe that they need to be started to be effective? These medications work best when taken within the first 48 hours of symptoms appearing by inhibiting the virus's ability to replicate and spread within the body The natural life history of flu is that the person will gradually improve, if they are improving and suddenly become worse that change needs to be medically evaluated. Some symptoms that need medical care are difficulty breathing, fever not reduced by antipyretics, change in mental status (always an emergency until you know why), if a pre-existing chronic illness is worsening, productive cough, development of a rash, and not being able to take enough fluids. Now we will look at pandemic influenza. Even though seasonal flu carries significant morbidity and mortality, influenza gets the most attention when pandemics occur. Humanity has no immunity to these novel viruses so many become ill, attack rates and death rates are high. Even if the illness course is not worse on an individual basis, and the case fatality rate is the same as seasonal flu, the “law of large numbers” holds that if attack rates are high in populations there will be large numbers of hospitalizations and deaths that can easily overwhelm healthcare systems. The Covid-19 pandemic has many comparisons to the 1918-19 influenza pandemic when the most notable and deadly influenza pandemic occurred. It was called the Spanish Flu. It did cause more severe illness on an individual basis as well. https://www.pbs.org/video/the-deadliest-flu-season-in- history-k9vpvf/ 30.What subtype caused the 1918 pandemic? The 1918 influenza pandemic was caused by theH1N1 subtype of the influenza A virus. 31.What other major world event happened at this time? How were they connected? The major world event happening concurrently was , and the war's close proximity and mass troop movements significantly facilitated the rapid spread of the virus globally. WWI Connection During World War I, large numbers of soldiers were densely packed together in close quarters, which created ideal conditions for the virus to spread rapidly across continents as troops traveled between battlefields. The last influenza pandemic was in 2009 caused by a new H1N1 virus, between those there were three others, 1957 Asian Flu, 1968 Hong Kong Flu, and 1976 Swine Flu. Go to the CDC 1918 Pandemic to answer these questions and watch the short video on the first page. https://www.cdc.gov/flu/pandemic-resources/1918- pandemic-h1n1.html 32.Unlike a typical flu season, the 2009 H1N1 what age group by far had the most hospitalizations and deaths? Globally, 80 percent of (H1N1)pdm09 virus-related deaths were estimated to have occurred in people younger than 65 years of age. This differs greatly from typical seasonal influenza epidemics, during which about 70 percent to 90 percent of deaths are estimated to occur in people 65 years and older.+ Children and young adults were hospitalized at higher rates. Children under 18 hospitalized ate highest rate vs. other age groups. Older adults 65+, had an increase in hospitalization rates, but lower vs. children and young adults. Watch this 14 minute video from the WHO about the history of pandemics and preparedness for the next flu pandemic, and how flu replicates in the body, and how the virus affects different species and transmits between them. https://www.who.int/multi-media/details/influenza-an-unpredictable-threat# This video was made before Covid showed us that coronaviruses can also evolve very rapidly! How the virus changes to cause a pandemic: because pigs and birds (which spread influenza through their GI tract in droppings) can get Type A influenza the same as humans, a rare event can happen that creates a new subtype of influenza A. This could happen on a farm for example where animals and people are in close proximity. Genes of the influenza virus are carried on 8 separate RNA segments – so if more than one subtype infects the same host (ex. a farmer has a seasonal flu infection and is exposed to an avian influenza and becomes infected with it too) viruses can exchange RNA during replication and create viruses with new gene combinations. This is called an antigenic shift and this is a big deal! A new subtype occurs to which humans have little to no immunity and this would have the potential to start a pandemic if the virus develops the ability to transmit from human to human. 33.So, an influenza pandemic is caused by an antigenic shift in an influenza virus – summarize in your own words how this occurs? Antigenic shift occurs when two or more flu viruses, commonly from different animal species (birds and pigs), affect the same cell at the same time. When inside the cell, their genes and genetic material become mixed and matched to become a entirely new virus. 34. How is it different from an antigenic drift that happens every year with flu viruses, creating the need to have new vaccines yearly? One way flu viruses change is called "antigenic drift." Drift consists of small changes (or mutations) in the genes of influenza viruses that can lead to changes in the surface proteins of the virus, HA (hemagglutinin) and NA (neuraminidase). The HA and NA surface proteins of influenza viruses are "antigens," which means they are recognized by the immune system and are capable of triggering an immune response, including production of antibodies that can fight infection. The changes associated with antigenic drift happen continually over time as flu viruses replicate (i.e., infect a host and make copies of themselves). Flu vaccines are designed to target one or more of the surface proteins/antigens of flu viruses. WHO influenza (avian and other zoonotic) page has good information and short videos to learn more about this. https://www.who.int/health-topics/influenza-avian- and-other-zoonotic#tab=tab_1 Now let’s look at influenza viruses that are particularly concerning and that scientist around the world watch out for (surveillance), especially any possible change where they transmit to humans. This group is called highly pathogenic avian influenza (HPAI). There are several currently under surveillance. We will look at one called H5N1 https://www.who.int/health-topics/influenza-avian-and-other- zoonotic#tab=tab_1 and https://www.who.int/publications/m/item/cumulative- number-of-confirmed-human-cases-for-avian-influenza-a(h5n1)-reported-to- who--2003-2023--3-october-2023 35.When was H5N1 first detected in humans? 1997 in Hong Kong Since that time, until March 2022, how many of those died and what does that make the case fatality rate (CFR) for H5NI, a HPAI virus? Deaths 500 from H5N1. CFR for H5N1 55%. 463 deaths/896 cases. HPAI Virus, like H5N1 remain traveling around the poultry population worldwide. Continuing to pose a constant threat to the health of humans. Recently, H5N1 outbreaks in animals are increasing around the globe. Review the CDC site for H5N1 Bird Flu Detections across the US https://www.cdc.gov/bird-flu/? CDC_AAref_Val=https://www.cdc.gov/flu/avianflu/data-map-commercial.html 36.How many states have had animal outbreaks? All 50 states have outbreaks in the wild birds and poultry populations. 37.How many human cases in the US? As of October 9, 2024, there have been 18 human cases of H5 bird flu reported in the United States since 2022, including 17 cases in 2024. 38.What people are most at risk during these outbreaks? Poultry Farmers Wildlife biologists Veterinarians Workers that handle and are in close contact with birds Anyone that is exposed to infected birds and or their droppings 39. What education is needed for the public and where should this be focused? Education focused on: Biosecurity for farms/backyard poultry Limiting contact with wild birds Maintaining hygiene (washing hands, disinfecting equipment) Report to authorities dead and sick birds Avian Flue Symptoms Risk of Transmission (R0) Let’s say you are caring for a cancer patient who has backyard chickens. Are there any concerns? Cancer patients will need to limit their exposure to backyard chickens. Strict hand hygiene practice will need to be followed, including regular hand washing, particularly after contact with chickens and their environment.  The patients healthcare provider will need to be made aware the patients exposure to the new environment and its new social determinants of health. The HCP can advise on additional precautions. Assess/Monitor the chickens for manifestations of illness and report the findings to a veterinarian Finally, view this short video about global surveillance and pandemic preparedness by WHO. Pandemic Influenza Preparedness Framework (PIP). Why is a global response necessary? What is the surveillance system called and what information does it give scientist and healthcare providers? https://www.who.int/multi-media/details/the-pip-framework# Extra sites about the 1918 pandemic (optional) 1918 pandemic influenza Https://www.google.com/search? sca_esv=659c37a8f6191013&rlz=1C1GCFQ_enUS1113US1113&q=1918+flu +pandemic&tbm=vid&source=lnms&fbs=AEQNm0Aa4sjWe7Rqy32pFwRj0Uk Wd8nbOJfsBGGB5IQQO6L3J5MIFhvnvU242yFxzEEp3BfRFWcyM5BvpTgNzM3vK j4sEjS6haKlrdzONTHhmt- ed8cx_khEa_Z3cHwHtSvIyjg7xgmEGmKplb9HWHYqGPmQro9SpPPefTzAjrxUaE t-vdHGpw8V_Ejf8N5KpE5WixjenkuLDZPsP5jg1aGCY- ZhKEvoWQ&sa=X&ved=2ahUKEwiA- JmNpvuIAxUsjIkEHexqD8UQ0pQJegQIEBAB&biw=1280&bih=631&dpr=1.5#fp state=ive&vld=cid:fceda844,vid:3x1aLAw_xkY,st:0 (Spanish Flu: a warning from history, Cambridge University) https://www.google.com/search? q=1918+flu+pandemic&rlz=1C1GCFQ_enUS1113US1113&oq=1918+&gs_lcr p=EgZjaHJvbWUqBwgCEAAYgAQyBggAEEUYOTIHCAEQABiABDIHCAIQABiABDI KCAMQABixAxiABDIKCAQQLhixAxiABDIHCAUQABiABDIHCAYQLhiABDIHCAcQA BiABDIHCAgQABiABDIHCAkQABiABNIBCTYzNTFqMGoxNagCCLACAQ&sourceid =chrome&ie=UTF-8#fpstate=ive&vld=cid:570954b5,vid:L6jTMacxzkI,st:0 (NIAID – What was the 1918 Influenza Pandemic? The Deadliest Pandemic ) https://www.google.com/search? q=1918+flu+pandemic&sca_esv=659c37a8f6191013&rlz=1C1GCFQ_enUS11 13US1113&tbm=vid&ei=uFQDZ4CCFeuuptQPkKHRwQM&start=10&sa=N&ve d=2ahUKEwiAvuebqfuIAxVrl4kEHZBQNDgQ8NMDegQIExAW&biw=1280&bih= 631&dpr=1.5#fpstate=ive&vld=cid:c4de3424,vid:lePhU_RA01k,st:0 (NIAID – Could the 1918 Influenza Pandemic Happen Again?) https://archive.cdc.gov/www_cdc_gov/flu/pandemic-resources/1918-comm emoration/1918-pandemic-history.htm https://www.paho.org/en/who-we-are/history-paho/purple-death-great- flu-1918  https://www.archives.gov/exhibits/influenza-epidemic/ and H5N1 https://www.who.int/news-room/questions-and-answers/item/influenza-h5n1 https://www.cdc.gov/bird-flu/situation-summary/index.html Optional sites to review to compare the Covid-19 pandemic with previous flu pandemics (Covid in the US has 103 million reported cases and 1.2 million deaths, globally 776 million cases and 7.1 million deaths) - https://data.who.int/dashboards/covid19/cases?n=o https://www.cdc.gov/museum/timeline/covid19.html CDC Museum COVID-19 Timeline COVID Data Tracker https://covid.cdc.gov/covid-data-tracker/#datatracker- home