 | This article contains instructions, advice, or how-to content .(March 2018) |
Influenza prevention involves taking steps that one can use to decrease their chances of contracting flu viruses, such as the Pandemic H1N1/09 virus, responsible for the 2009 flu pandemic.
People who contract influenza are most infective between the second and third days after infection, and infectivity lasts for around ten days. [1] Children are much more infectious than adults and shed virus from just before they develop symptoms until two weeks after infection. [1] [2] The transmission of influenza can be modeled mathematically, which helps predict how the virus will spread in a population. [3]
Influenza can be spread in three main ways: [4] [5]
The relative importance of these three modes of transmission is unclear, and they may all contribute to the spread of the virus. [7] [8] In the airborne route, the droplets that are small enough for people to inhale are 0.5 to 5 μm in diameter and inhaling just one droplet might be enough to cause an infection. [4] Although a single sneeze releases up to 40,000 droplets, [9] most of these droplets are quite large and will quickly settle out of the air. [4] How long influenza survives in airborne droplets seems to be influenced by the levels of humidity and UV radiation: with low humidity and a lack of sunlight in winter probably aiding its survival. [4]
As the influenza virus can persist outside of the body, it can also be transmitted by contaminated surfaces such as banknotes, [10] doorknobs, light switches and other household items. [11] The length of time the virus will persist on a surface varies, with the virus surviving for one to two days on hard, non-porous surfaces such as plastic or metal, for about fifteen minutes from dry paper tissues, and only five minutes on skin. [12] However, if the virus is present in mucus, this can protect it for longer periods. [4] Avian influenza viruses can survive indefinitely when frozen. [13] They are inactivated by heating to 56 °C (133 °F) for a minimum of 60 minutes, as well as by acids (at pH <2). [13]
According to the World Health Organization (WHO), the "main route of transmission of the pandemic influenza virus seems to be similar to seasonal influenza, via droplets that are expelled by speaking, sneezing or coughing." [14] One of WHO's recommendations is to "keep your distance from people who show symptoms of influenza-like illness, such as coughing and sneezing (trying to maintain a distance of about 1 metre if possible)." [14] Other WHO recommendations are listed below.
The American Centers for Disease Control and Prevention (CDC) agrees that the "spread of novel H1N1 virus is thought to occur in the same way that seasonal flu spreads. Flu viruses are spread mainly from person to person through coughing or sneezing by people with influenza." [6] The CDC also says that a person may become infected if he or she touches something with flu viruses on it "and then touches his or her eyes, nose, or mouth." [6]
Researchers have demonstrated anti-bodies against H1N1 variant influenza in 10 to 7 percent of workers and residents of swine farms in Jiangsu Province, China. Residents of a nearby city did not have detectable anti-bodies to H1N1 variant influenza. [15]
Reasonably effective ways to reduce the transmission of influenza include good personal health and hygiene habits such as: not touching your eyes, nose or mouth; [6] frequent hand washing (with soap and water, or with alcohol-based hand rubs); [6] eating a diet rich in fruits and vegetables; [16] covering coughs and sneezes; avoiding close contact with sick people; and staying home yourself if you are sick. Avoiding spitting is also recommended. [17]
Although face masks might help prevent transmission when caring for the sick, [18] [19] there is mixed evidence on beneficial effects in the community. [17] [20] Smoking raises the risk of contracting influenza, as well as producing more severe disease symptoms. [21] [22] [23] [24] [25] Thus, according to the laws of mathematical modelling of infectious diseases, smokers raise the exponential growth rates of influenza epidemics and may indirectly be responsible for a large percentage of influenza cases.[ citation needed ]
Since influenza spreads through both aerosols and contact with contaminated surfaces, surface sanitizing may help prevent some infections. [26] Alcohol is an effective sanitizer against influenza viruses, while quaternary ammonium compounds can be used with alcohol so that the sanitizing effect lasts for longer. [27] In hospitals, quaternary ammonium compounds and bleach are used to sanitize rooms or equipment that have been occupied by patients with influenza symptoms. [27] At home, this can be done effectively with a diluted chlorine bleach. [28]
Social distancing strategies used during past pandemics, such as closing schools, churches and theaters, slowed the spread of the virus but did not have a large effect on the overall death rate. [29] [30] It is uncertain if reducing public gatherings, by for example closing schools and workplaces, will reduce transmission since people with influenza may just be moved from one area to another; such measures would also be difficult to enforce and might be unpopular. [17] When small numbers of people are infected, isolating the sick might reduce the risk of transmission. [17]
According to studies conducted in Australia and Japan, screening individuals for influenza symptoms at airports during the 2009 H1N1 outbreak was not an effective method of infection control. [31] [32]
The Centers for Disease Control and Prevention (CDCP) recommends that businesses promote and administer annual flu vaccination within the workplace. Additional measures include reducing potential for exposure through increasing awareness of flu symptoms, using good cough and sneeze etiquette, staying home when ill, and frequent hand washing. [33]
The Occupational Health and Safety Administration (OSHA) recommends these controls to employers to decrease transmission of influenza in the workplace: [34]
Specific occupations with increased risk of influenza infection include health care, education and child care, air line industry, and agricultural workers.
According to the WHO, the following steps can decrease one's chance of contracting the flu virus: [14]
The CDCP lists these as important ways to lower the risk of transmission: [6]
Watch for emergency warning signs that need urgent medical attention. These warning signs include:[ citation needed ]
In the 2009 pandemic, the initial demand for vaccine greatly outstripped the supply. [36]
As the 2009 pandemic got underway, the first vaccine to become available in the United States by mid-October 2009 was about 2.2 million doses of the weakened live-virus nasal spray formulation. This form was not then recommended for some of the people who were at highest risk of complications from flu, including pregnant women and people with asthma.[ citation needed ] The attenuated live virus was instead suggested to be used to allow some priority groups like health care workers and healthy children 2 or older, to allow them to be vaccinated immediately. Those to whom the weakened virus might pose a heightened risk were recommended to wait for the release of killed-virus vaccines, which followed weeks to months later.[ citation needed ]
Vaccine uptake by the public was very low in the UK, but predicted by greater belief in the vaccine's efficacy and safety and a greater perceived risk of the disease. [37]
A survey of Americans done in late June 2009 by the Harvard School of Public Health found that roughly 90% said they would be willing to avoid shopping malls, movie theaters, public transportation, and worship services for more than two weeks if health officials told them to. It also found that parents were worried about closures of schools or day care centers, with 43% saying they would lose pay or have money problems if they had to stay home a week or more because they were sick or had to care for someone. [38] [39] In the UK, the government established a National Pandemic Flu Service with a hotline and website, enabling persons with symptoms to get advice or obtain drugs without first getting a prescription from a doctor. [40]
Individuals with increased exposure to animals, especially birds and swine, are at increased risk of variant influenza infection. This includes agricultural workers, as well as residents of farms, individuals who keep swine and/or birds as pets, and animal exhibitors. Variant influenza viruses do not normally infect humans, but when they do cause human infection, the virus can be passed from animals to humans directly, or between humans. [41] Due to human to human transmission, family and close contacts of agricultural workers are at increased risk of influenza as well. Unfortunately, there is also decreased access to health care in agricultural communities which makes prevention and response to influenza outbreaks more difficult. [42] During the 2009 H1N1 pandemic, multiple factors were identified as increasing the vulnerability of agricultural workers and their communities. These factors included substandard housing, immigration status, scape-goating, economic barriers, communication and cultural barriers, and discrimination. [42] [43] Steege et al., found that 75% of agricultural workers were uninsured, making them less likely to receive the flu vaccine and less likely to seek care when ill. [43]
Public health recommendations for agricultural communities: [43]
Recommendations for agricultural workers and exhibitors: [44]
Additional recommendations for visitors to agricultural exhibits: [15]
Influenza A virus (IAV) is the only species of the genus Alphainfluenzavirus of the virus family Orthomyxoviridae. It is a pathogen with strains that infect birds and some mammals, as well as causing seasonal flu in humans. Mammals in which different strains of IAV circulate with sustained transmission are bats, pigs, horses and dogs; other mammals can occasionally become infected.
Avian influenza, also known as avian flu or bird flu, is a disease caused by the influenza A virus, which primarily affects birds but can sometimes affect mammals including humans. Wild aquatic birds are the primary host of the influenza A virus, which is enzootic in many bird populations.
Oseltamivir, sold under the brand name Tamiflu among others, is an antiviral medication used to treat and prevent influenza A and influenza B, viruses that cause the flu. Many medical organizations recommend it in people who have complications or are at high risk of complications within 48 hours of first symptoms of infection. They recommend it to prevent infection in those at high risk, but not the general population. The Centers for Disease Control and Prevention (CDC) recommends that clinicians use their discretion to treat those at lower risk who present within 48 hours of first symptoms of infection. It is taken by mouth, either as a pill or liquid.
Influenza A virus subtype H5N1 (A/H5N1) is a subtype of the influenza A virus, which causes the disease avian influenza. It is enzootic in many bird populations, and also panzootic. A/H5N1 virus can also infect mammals that have been exposed to infected birds; in these cases, symptoms are frequently severe or fatal.
Influenza vaccines, colloquially known as flu shots or the flu jab, are vaccines that protect against infection by influenza viruses. New versions of the vaccines are developed twice a year, as the influenza virus rapidly changes. While their effectiveness varies from year to year, most provide modest to high protection against influenza. Vaccination against influenza began in the 1930s, with large-scale availability in the United States beginning in 1945.
An agricultural show is a public event exhibiting the equipment, animals, sports and recreation associated with agriculture and animal husbandry. The largest comprise a livestock show, a trade fair, competitions, and entertainment. The work and practices of farmers, animal fanciers, cowboys, and zoologists may be displayed. The terms agricultural show and livestock show are synonymous with the North American terms county fair and state fair.
Swine influenza is an infection caused by any of several types of swine influenza viruses. Swine influenza virus (SIV) or swine-origin influenza virus (S-OIV) refers to any strain of the influenza family of viruses that is endemic in pigs. As of 2009, identified SIV strains include influenza C and the subtypes of influenza A known as H1N1, H1N2, H2N1, H3N1, H3N2, and H2N3.
Flu season is an annually recurring time period characterized by the prevalence of an outbreak of influenza (flu). The season occurs during the cold half of the year in each hemisphere. It takes approximately two days to show symptoms. Influenza activity can sometimes be predicted and even tracked geographically. While the beginning of major flu activity in each season varies by location, in any specific location these minor epidemics usually take about three weeks to reach its pinnacle, and another three weeks to significantly diminish.
Influenza A virus subtype H1N1 (A/H1N1) is a subtype of influenza A virus (IAV). Some human-adapted strains of H1N1 are endemic in humans and are one cause of seasonal influenza (flu). Other strains of H1N1 are endemic in pigs and in birds. Subtypes of IAV are defined by the combination of the antigenic H and N proteins in the viral envelope; for example, "H1N1" designates an IAV subtype that has a type-1 hemagglutinin (H) protein and a type-1 neuraminidase (N) protein.
An influenza pandemic is an epidemic of an influenza virus that spreads across a large region and infects a large proportion of the population. There have been five major influenza pandemics in the last 140 years, with the 1918 flu pandemic being the most severe; this is estimated to have been responsible for the deaths of 50–100 million people. The 2009 swine flu pandemic resulted in under 300,000 deaths and is considered relatively mild. These pandemics occur irregularly.
Influenza A virus subtype H3N2 (A/H3N2) is a subtype of influenza A virus (IAV). Some human-adapted strains of A/H3N2 are endemic in humans and are one cause of seasonal influenza (flu). Other strains of H1N1 are endemic in pigs and in birds. Subtypes of IAV are defined by the combination of the antigenic H and N proteins in the viral envelope; for example, "H1N1" designates an IAV subtype that has a type-1 hemagglutinin (H) protein and a type-1 neuraminidase (N) protein.
Canine influenza is influenza occurring in canine animals. Canine influenza is caused by varieties of influenzavirus A, such as equine influenza virus H3N8, which was discovered to cause disease in canines in 2004. Because of the lack of previous exposure to this virus, dogs have no natural immunity to it. Therefore, the disease is rapidly transmitted between individual dogs. Canine influenza may be endemic in some regional dog populations of the United States. It is a disease with a high morbidity but a low incidence of death.
Pandemrix is an influenza vaccine for influenza pandemics, such as the 2009 flu pandemic. The vaccine was developed by GlaxoSmithKline (GSK) and patented in September 2006.
Influenza, commonly known as the flu, is an infectious disease caused by influenza viruses. Symptoms range from mild to severe and often include fever, runny nose, sore throat, muscle pain, headache, coughing, and fatigue. These symptoms begin one to four days after exposure to the virus and last for about two to eight days. Diarrhea and vomiting can occur, particularly in children. Influenza may progress to pneumonia from the virus or a subsequent bacterial infection. Other complications include acute respiratory distress syndrome, meningitis, encephalitis, and worsening of pre-existing health problems such as asthma and cardiovascular disease.
Influenza-like illness (ILI), also known as flu-like syndrome or flu-like symptoms, is a medical diagnosis of possible influenza or other illness causing a set of common symptoms. These include fever, shivering, chills, malaise, dry cough, loss of appetite, body aches, nausea, and sneezing typically in connection with a sudden onset of illness. In most cases, the symptoms are caused by cytokines released by immune system activation, and are thus relatively non-specific.
The 2009 swine flu pandemic, caused by the H1N1/swine flu/influenza virus and declared by the World Health Organization (WHO) from June 2009 to August 2010, was the third recent flu pandemic involving the H1N1 virus. The first identified human case was in La Gloria, Mexico, a rural town in Veracruz. The virus appeared to be a new strain of H1N1 that resulted from a previous triple reassortment of bird, swine, and human flu viruses which further combined with a Eurasian pig flu virus, leading to the term "swine flu".
The 2009 flu pandemic in the United States was caused by a novel strain of the Influenza A/H1N1 virus, commonly referred to as "swine flu", that was first detected on 15 April 2009. While the 2009 H1N1 virus strain was commonly referred to as "swine flu", there is no evidence that it is endemic to pigs or of transmission from pigs to people; instead, the virus spreads from person to person. On April 25, the World Health Organization declared a public health emergency, followed concurringly by the Obama administration on April 26.
The pandemic H1N1/09 virus is a swine origin influenza A virus subtype H1N1 strain that was responsible for the 2009 swine flu pandemic. This strain is often called swine flu by the public media due to the prevailing belief that it originated in pigs. The virus is believed to have originated around September 2008 in central Mexico.
The 2009 swine flu pandemic vaccines were influenza vaccines developed to protect against the pandemic H1N1/09 virus. These vaccines either contained inactivated (killed) influenza virus, or weakened live virus that could not cause influenza. The killed virus was injected, while the live virus was given as a nasal spray. Both these types of vaccine were produced by growing the virus in chicken eggs. Around three billion doses were produced, with delivery in November 2009.
Influenza A virus subtype H7N9 (A/H7N9) is a subtype of the influenza A virus, which causes influenza (flu), predominantly in birds. It is enzootic in many bird populations. The virus can spread rapidly through poultry flocks and among wild birds; it can also infect humans that have been exposed to infected birds.
{{cite journal}}: CS1 maint: DOI inactive as of January 2025 (link)