Other activities that may be performed to prevent getting influenza include: Hand washing and using alcohol-based hand sanitizers, Covering your coughs and sneezes with a disposable tissue or your arm or sleeve, Avoiding touching your eyes, nose, or mouth, Avoiding close contact with persons who are ill, Staying home when you are ill, and Taking antiviral medications if prescribed by your doctor.
In certain situations e. HCP must be fit tested for N95 masks. When the patient arrives at the HCF, the patient should be placed in airborne isolation i. Transmission on the hands of patients and their caregivers has also been described as being potentially relevant. Another potential transmission routes is contact with fomites[ 24 ] contaminated with respiratory or gastrointestinal fluids. In the early epidemic phase, most of the cases were imported, whereas currently the majority of cases are autochthonous.
Schools represent the ideal environment for influenza virus transmission because of crowding and close contact between children, who usually share items and toys. Indeed, school clusters have been described everywhere. Table 1 shows some recommendations for minimizing the diffusion of S-OIV in community settings[ 33 ].
Influenza is the most frequent cause of acute respiratory illness requiring medical intervention. According to this data, S-OIV patients complained mostly of the classical influenza symptoms; in addition, S-OIV patients also often have diarrhea and vomiting, which are not usually seen in seasonal influenza.
Other symptoms reported by patients include myalgia, arthralgia, nasal congestion, headache, anorexia, sneezing, nausea, shortness of breath, and conjunctivitis. The younger age-groups appear to be much more susceptible than the elderly to S-OIV infection. One of the more controversial issues is the question of hospitalization for S-OIV infection; hospitalization is often deemed necessary because of the need for isolation of these patients. During the influenza seasons of —, the average seasonal burden due to influenza was estimated to be about 50 hospitalizations per , US inhabitants per season.
Later, cases were isolated in hospitals and quarantine was practised in most European countries though not in the UK. In this phase of the pandemic, most national and international guidelines recommend that individuals with suspected flu be treated at home so as to avoid contact with other people. In case of any of the emergency warning signs, which includes difficulty breathing, confusion, severe or persistent vomiting, and worsening of cough, urgent medical attention is required.
Patients who present with flu-like symptoms and then improve, only to return with fever and a worse cough than before, should be suspected to have respiratory complications. For patients at high risk for developing influenza complications see below , hospital admission should be considered. In the case of hospital admission, patients who are confirmed, probable, or suspected cases should be placed directly into individual rooms and the door should be kept closed.
Healthcare personnel interacting with these patients should adhere to the guidelines for proper hand hygiene. Nonsterile gloves and gowns should be donned, and eye protection and respiratory protection ensured, before entering the patient's room.
Isolation precautions should be continued for 7 days from symptom onset or until resolution of symptoms. Pneumonia is the most common complication of seasonal influenza. This complication is rare in interpandemic eras but becomes more frequent when a pandemic occurs. From March 24 to April 29, , a total of cases of severe pneumonia were reported in Mexico. Data from the literature reported 79 cases of pneumonia [ Table 3 ]; however, rates of pneumonia complication varied according to the population on study.
In Mexico, among 98 patients hospitalized for acute respiratory illness at the National Institute of Respiratory Diseases in Mexico City during the early stages of the influenza A H1N1 outbreak, 18 cases of pneumonia and confirmed S-OIV infection were identified. All these patients had bilateral pneumonia and had complaints of fever, cough, and dyspnea. Twelve patients required mechanical ventilation and seven died. These patients were aged 7—17 years and were admitted with signs of influenza-like illness and seizures or altered mental status.
Three of the four patients had abnormal electroencephalograms EEGs. All four patients recovered fully and had no neurologic sequelae at discharge. These findings indicate that, as with seasonal influenza, neurologic complications can occur after respiratory tract infection with novel influenza A H1N1. The risk of morbidity from seasonal influenza is higher among pregnant women.
Pregnant women with underlying medical conditions such as asthma are at particularly high risk for influenza-related complications.
Four women had confirmed pneumonia. WHO strongly recommends that in areas where S-OIV infection is widespread pregnant women, as well as the clinician treating them, be alert to symptoms of influenza-like illness. In addition to the increased risk for pregnant women, groups at increased risk of severe or fatal illness include people with underlying medical conditions, particularly chronic lung disease, cardiovascular disease, diabetes, and immunosuppression.
Some preliminary studies suggest that extreme obesity represents a risk factor for severe disease. Two classes of antiviral drugs are available for the treatment of influenza: neuraminidase inhibitors, zanamivir and oseltamivir and adamantanes amantadine and rimantadine.
At the beginning of the S-OIV pandemic, the use of neuraminidase inhibitors was encouraged because oseltamivir and zanamivir have been proven to be able to reduce the duration and the incidence of complications of seasonal influenza,[ 78 ] especially when treatment is started early ideally, within 48 h of the onset of symptoms. As more data on antiviral effectiveness, clinical features of illness, adverse events from antiviral use, and antiviral susceptibility become available, recommendations on treatment are changing.
Until the year , resistance of influenza A H1N1 virus to neuraminidase agents occurred only in a small proportion of cases. Till date, the use of oseltamivir and zanamivir has been restricted to patients at relatively higher risk for influenza complications,[ 79 ] i. The CDC suggest that antiviral chemoprophylaxis with either oseltamivir or zanamivir can be considered for the following[ 78 ]:. Close contacts of cases confirmed, probable, or suspected who are at high risk for complications of influenza.
Health care personnel, public health workers, or first responders who have had a recognized, unprotected close contact exposure to a person with novel H1N1 influenza virus infection confirmed, probable, or suspected during that person's infectious period.
However, several issues exist around vaccine manufacture and approval, as well as production capacity. WHO conducted a survey in collaboration with all influenza vaccine manufacturers to review the current status of northern hemisphere seasonal vaccine production, and to assess the capabilities of the manufacturers for supplying the new influenza A H1N1 vaccine over a 1-year period.
The survey showed that by the time of the expected new epidemic wave most manufacturers will be technically ready to initiate large-scale production of the pandemic influenza vaccine. However, there are still many controversies regarding the number of vaccine doses required to achieve full immunological protection and the possible utility of adjuvants.
There is also great concern related to the fast-track approval processes for the H1N1 vaccine set up by many regulatory agencies since this means that a vaccine might be licensed for use without satisfying the usual safety and efficacy requirements. For instance, the emergence of swine influenza at Fort Dix in led to the implementation of a mass vaccination program, with 40 million civilian vaccinations. Another important query is who should be prescribed the H1N1 vaccine.
Seasonal influenza vaccine is currently provided to all persons who wish to reduce the risk for becoming ill with influenza or of transmitting it to others. Countries need to determine their order of priority based on country-specific conditions, in order to deliver vaccination to priority groups and to groups with a social utility.
People aged 25—64 years with underlying medical conditions e. Other times, the infections occur because of changes in the influenza virus. Flu viruses constantly change, and the changes can happen slowly over time or suddenly. Sometimes, the changes result in viruses that spread more easily from animals to humans. Flu viruses can change through antigenic drift or antigenic shift:. An influenza pandemic is a worldwide outbreak of disease.
This occurs when an influenza virus undergoes an antigenic shift and creates a completely new subtype of influenza A with the ability to cause illness in people and spread easily from person-to-person. We are not currently experiencing an influenza pandemic. However, two identified avian bird influenza viruses have the potential to cause a pandemic—H5N1 and H7N9.
Because H5N1 and H7N9 do not circulate in humans, people have little to no immunity against these viruses. Human infections with these viruses have happened rarely, but if either virus changes in such a way that it is able to infect humans easily and spread easily from person-to-person, an influenza pandemic could result. Flu influenza viruses are divided into four broad categories: influenza A, B, C or D.
Influenza A is the most common type. H1N1 flu is a subtype of influenza A. Subtypes of influenza A are categorized based on two proteins on the surface of the virus, hemagglutinin H and neuraminidase N.
There are many H and N subtypes, and each one is numbered. All H and N flu subtypes are influenza A viruses. Each influenza subtype has many different strains of influenza virus. Not all strains infect people. Each year's flu vaccine includes varieties of both of these strains and influenza B.
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