Swine flu is presumptively diagnosed clinically by the patient's history of association with people known to have the disease and their symptoms listed above.
Usually, a quick test (for example, nasopharyngeal swab sample) is done to see if the patient is infected with influenza A or B virus. Most of the tests can distinguish between A and B types. The test can be negative (no flu infection) or positive for type A and B. If the test is positive for type B, the flu is not likely to be swine flu. If it is positive for type A, the person could have a conventional flu strain or swine flu. However, the accuracy of these tests has been challenged, and the U.S. Centers for Disease Control and Prevention (CDC) has not completed their comparative studies of these tests. However, a new test developed by the CDC and a commercial company reportedly can detect H1N1 reliably in about one hour; the test was formerly only available to the military. In 2010, the FDA approved a commercially available test that could detect H1N1 within four hours. Most of these rapid tests are based on PCR technology.
Swine flu is definitively diagnosed by identifying the particular antigens (surface proteins) associated with the virus type. In general, this test is done in a specialized laboratory and is not done by many doctors' offices or hospital laboratories. However, doctors' offices are able to send specimens to specialized laboratories if necessary. Because of the large number of novel H1N1 swine flu cases that occurred in the 2009-2010 flu season (the vast majority of flu cases [about 95%-99%] were due to novel H1N1 flu viruses), the CDC recommended only hospitalized patients' flu virus strains be sent to reference labs to be identified. H3N2v flu strains and other flu virus strains are diagnosed by similar methods
The best treatment for influenza infections in humans is prevention by vaccination. Work by several laboratories has produced vaccines. The first H1N1 vaccine released in early October 2009 was a nasal spray vaccine that was approved for use in healthy individuals ages 2-49. The injectable vaccine, made from killed H1N1, became available in the second week of Oct. 2009. This vaccine was approved for use in ages 6 months to the elderly, including pregnant females. Both of these vaccines were approved by the CDC only after they had conducted clinical trials to prove that the vaccines were safe and effective. A new influenza vaccine preparation is the intradermal (trivalent) vaccine is available; it works like the shot except the administration is less painful. It is approved for ages 18-64 years.
Almost all vaccines have some side effects. Common side effects of H1N1 vaccines (alone or in combination with other flu viral strains) are typical of flu vaccines used over many years and are as follows:
• Flu shot: Soreness, redness, minor swelling at the shot site, muscle aches, low-grade fever, and nausea do not usually last more than about 24 hours.
• Nasal spray: runny nose, low-grade fever, vomiting, headache, wheezing, cough, and sore throat
• Intradermal shot: redness, swelling, pain, headache, muscle aches, fatigue
The flu shot (vaccine) is made from killed virus particles so a person cannot get the flu from a flu shot. However, the nasal spray vaccine contains live virus that have been altered to hinder its ability to replicate in human tissue. People with a suppressed immune system should not get vaccinated with the nasal spray.
Also, most vaccines that contain flu viral particles are cultivated in eggs, so individuals with an allergy to eggs should not get the vaccine unless tested and advised by their doctor that they are cleared to obtain it. Like all vaccines, rare events may occur in some rare cases (for example, swelling, weakness, or shortness of breath). If any symptoms like these develop, the person should see a physician immediately.
Two antiviral agents have been reported to help prevent or reduce the effects of swine flu. They are zanamivir (Relenza) and oseltamivir (Tamiflu), both of which are also used to prevent or reduce influenza A and B symptoms. These drugs should not be used indiscriminately, because viral resistance to them can and has occurred. Also, they are not recommended if the flu symptoms already have been present for 48 hours or more, although hospitalized patients may still be treated past the 48-hour guideline. Severe infections in some patients may require additional supportive measures such as ventilation support and treatment of other infections like pneumonia that can occur in patients with a severe flu infection. The CDC has suggested in their guidelines that pregnant females can be treated with the two antiviral agents.
On Dec. 22, 2014, the FDA approved the first new anti-influenza drug (for H1N1 and other influenza virus types) in 15 years, peramivir injection (Rapivab). It is approved for use in the following settings:
Diarrhea, skin infections, hallucinations, and/or altered behavior may occur as side effects of this drug.
• Adult patients for whom therapy with an intravenous (IV) medication is clinically appropriate, based upon one or more of the following reasons:
The patient is not responding to either oral or inhaled antiviral therapy, or
drug delivery by a route other than IV is not expected to be dependable or is not feasible, or
the physician decides that IV therapy is appropriate due to other circumstances.
• Pediatric patients for whom an intravenous medication clinically appropriate because:
The patient is not responding to either oral or inhaled antiviral therapy, or
drug delivery by a route other than IV is not expected to be dependable or is not feasible.
In 1976, there was an outbreak of swine flu at Fort Dix. This virus was not the same as the 2009 H1N1 outbreak, but it was similar insofar as it was an influenza A virus that had similarities to the swine flu virus. There was one death at Fort Dix. The government decided to produce a vaccine against this virus, but the vaccine was associated with rare instances of neurological complications (Guillain-Barré syndrome) and was discontinued. Some individuals speculate that formalin, used to inactivate the virus, may have played a role in the development of this complication in 1976. One of the reasons it takes a few months to develop a new vaccine is to test the vaccine for safety to avoid the complications seen in the 1976 vaccine. Individuals with active infections or diseases of the nervous system are also not recommended to get flu vaccines.
Vaccination to prevent influenza is particularly important for people who are at increased risk for severe complications from influenza or at higher risk for influenza-related doctor or hospital visits. When vaccine supply is limited, vaccination efforts should focus on delivering vaccination to the following people since these populations have a higher risk for H1N1 and some other viral infections according to the CDC:
• All children 6 months to 4 years (59 months) of age
• All people 50 years of age and older
• Adults and children who have chronic pulmonary (including asthma) or cardiovascular (except isolated hypertension), renal, hepatic, neurological, hematologic, or metabolic disorders (including diabetes mellitus)
• People who have immunosuppression (including immunosuppression caused by medications or by HIV)
• Women who are or will be pregnant during the influenza season
• Children and adolescents (6 months to 18 years of age) who are receiving long-term aspirin therapy and who might be at risk for experiencing Reye's syndrome after influenza virus infection
• Residents of nursing homes and other long-term-care facilities
• American Indians/Alaska natives
• People who are morbidly obese (BMI ≥40)
• Health-care professionals (doctors, nurses, health-care personnel treating patients)
• Household contacts and caregivers of children under 5 years of age and adults 50 years of age and older, with particular emphasis on vaccinating contacts of children less than 6 months age
• Household contacts and caregivers of people with medical conditions that put them at higher risk for severe complications from influenza
Can swine flu be prevented with a vaccine?
The CDC recommends for the 2014-2015 flu season that everyone 6 months old and older should get a flu shot to prevent or reduce the chance of getting the flu. The best way to prevent novel H1N1 swine flu is vaccination. The 2014 CDC recommendations that apply to H1N1, H3N2, and other flu viruses are almost identical to those above-mentioned recommendations for patients at risk when vaccine doses are limited and are as follows:
• Are aged 6 months through 4 years (59 months)
• Are aged 50 years and older
• Have chronic pulmonary (including asthma), cardiovascular (except hypertension), renal, hepatic, neurologic, hematologic, or metabolic disorders (including diabetes mellitus)
• Are immunosuppressed (including immunosuppression caused by medications or by human immunodeficiency virus)
• Are or will be pregnant during the influenza season
• Are aged 6 months through 18 years and receiving long-term aspirin therapy and who therefore might be at risk for experiencing Reye's syndrome after influenza virus infection
• Are residents of nursing homes and other chronic-care facilities
• Are American Indians/Alaska Natives
• Are morbidly obese (body-mass index is 40 or greater)
• Are health-care personnel
• Are household contacts and caregivers of children aged younger than 5 years and adults aged 50 years and older, with particular emphasis on vaccinating contacts of children aged younger than 6 months
• Are household contacts and caregivers of people with medical conditions that put them at higher risk for severe complications from influenza
• As in previous recommendations, all children aged 6 months to 8 years of age who receive a seasonal influenza vaccine for the first time should receive two doses. Children who received only one dose of a seasonal influenza vaccine in the first influenza season should receive two doses rather than one in the following influenza season.
• A newly approved inactivated trivalent vaccine containing 60 mcg of hemagglutinin antigen per influenza vaccine virus strain (Fluzone High-Dose [Sanofi Pasteur]) is an alternative inactivated vaccine for people 65 years of age and older.
The CDC occasionally makes changes and updates its information on vaccines and other recommendations about the current flu pandemic. The CDC states, "for the most accurate health information, visit http://www.cdc.gov , 24/7." Caregivers should check the vaccine package inserts for more detailed information on the vaccines when they become available.
The CDC says that a good way to prevent any flu disease is to avoid exposure to the virus; this is done by frequent hand washing, not touching your hands to your face (especially the nose and mouth), and avoiding any close proximity to or touching any person who may have flu symptoms. Since the virus can remain viable and infectious for about 48 hours on many surfaces, good hygiene and cleaning with soap and water or alcohol-based hand disinfectants are also recommended. Some physicians say face masks may help prevent getting airborne flu viruses (for example, from a cough or sneeze), but others think the better use for masks would be on those people who have symptoms and sneeze or cough.
The use of Tamiflu or Relenza may help prevent the flu if taken before symptoms develop or reduce symptoms if taken within about 48 hours after symptoms develop. Some investigators say that administration of these drugs is still useful after 48 hours, especially in high-risk patient populations. However, taking these drugs is not routinely recommended for prevention for the healthy population because investigators suggest that as occurs with most drugs, flu strains will develop resistance to these medications. During the H1N1 pandemic, the CDC made further suggestions about the use of these antiviral medications and developed the interim guidelines for use of Tamiflu and Relenza as follows, and this has not changed for the 2014-2015 flu season:
1. Patients with high-risk factors should discuss flu symptoms and when to use antiviral medications; doctors should provide a prescription for the antiviral drug for the patient to use if the patient is exposed to flu or develops flu-like symptoms without having to go in to see the doctor.
2. "Watchful waiting" was added as a response to taking antiviral medications, with the emphasis on the fact that those people who develop fever and have a preexisting health condition should then begin the antiviral medication.
3. The antiviral medications are the first-line medicines for treatment of novel H1N1, H3N2, and H3N2v flu, and most cases are to date susceptible to Tamiflu and Relenza.
In general, preventive measures to prevent the spread of flu are often undertaken by those people who have symptoms. Symptomatic people should stay at home, avoid crowds, and take off from work or school until the disease is no longer transmittable (about two to three weeks) or until medical help and advice is sought. Sneezing, coughing, and nasal secretions need to be kept away from other people; simply using tissues and disposing of them will help others.
Quarantining patients is usually not warranted, but such measures depend on the severity of the disease. The CDC recommends that people who appear to have an influenza-like illness upon arrival at work or school or become ill during the day be promptly separated from other people and be advised to go home until at least 24 hours after they are free of fever (100 F [37.8 C] or greater), or signs of a fever, without the use of fever-reducing medications. The novel H1N1 swine flu disease takes about seven to 10 days before fevers stop, but research data suggests waiting until the cough is gone since many people are still infectious about one week after fever is gone. However, the CDC did not extend their recommendations to stay home for that extra week.
Can swine flu be prevented if the swine flu vaccine (or other flu strain vaccines) is not readily available?
Although vaccination is the best way to prevent the swine flu, there may be times in the future when vaccine may not be available. Currently, there are no shortages of the trivalent flu vaccine that contains H1N1 antigens. However, during the 2009 H1N1 pandemic, this situation did occur so people wanted to know what they could do to protect themselves. If, in the future, vaccine supplies do not meet demands, there are some things people can do to try and prevent infection. Without vaccination, the best strategy is to not allow any virus type to contact a person's mucus. Quarantining any virus-infected people is an extreme measure that may work in some instances (for example, China used this method), but even with quarantining, the virus may still spread by people who have minimal or no symptoms.
The next step, that is easier to be implemented by individuals, is for people with the disease to self-quarantine until they become noninfectious (about seven to 10 days after flu symptoms abate). Infected people can wear surgical masks to reduce the amount of droplet spray from coughs and sneezes and throw away contaminated tissues. Unfortunately, these approaches depend on the compliance of many other people, and the likelihood that such methods will be highly successful in preventing flu virus infections, at best, is only fair. Such methods did not stop the 2009 H1N1 pandemic, although they may have some benefit for a few individuals.
Yet there are still some other methods available to individuals. Perhaps the best way for individuals to try to prevent flu virus infection is a combination of methods that are aimed at fulfilling the very basic principle that if the virus doesn't reach an individual's mucus membrane cells, infection will be prevented. The methods are as follows:
1. Kill or inactivate the virus before it reaches a human cell by using soap and water to clean your hands; washing clothing and taking a shower will do the same for the rest of your body.
2. Use an alcohol-based hand sanitizer if soap and water are not readily available, and use sanitizers on objects that many people may touch (for example, doorknobs, computer keyboards, handrails, phones), although some researchers suggest that such sanitizers are generally ineffective.
3. Do not touch your mouth, eyes, nose, unless you first do items 1 or 2 above.
4. Avoid crowds, parties, and especially people who are coughing and sneezing (most virus-containing droplets do not travel more than 4 feet, so experts suggest 6 feet away is a good distance to stay). If you cannot avoid crowds (or parties), try to remain aware of people around you and use the 6-foot rule with anyone coughing or sneezing. Do not reach for or eat snacks out of canisters or other containers at parties.
5. Avoid touching anything within about 6 feet of an uncovered cough/sneeze, because the droplets that contain virus fall and land on anything usually within that range.
6. Studies show that individuals who wear surgical or N95 particle masks may prevent inhalation of some H1N1 virus, but the masks may prevent only about 50% of airborne exposures and offer no protection against surface droplets. However, masks on H1N1 infected people can markedly reduce the spread of infected droplets.
These six steps can help prevent individuals from getting H1N1 and other types of infection, but for many people, adherence to them may be difficult at best. However, there are some additional strategies that may also help prevent viral infections in unvaccinated people according to some investigators. Saline nasal washes and gargling with saline (or a commercial product) as a way to reduce or eliminate viral virus from mucus membranes has been suggested. Proponents of these methods base their rationale on the fact that flu viruses usually take about two to three days to proliferate in nasal/throat cells. While nasal washes and gargling may be soothing to some people, there are no studies that indicate H1N1or other viruses are killed, inactivated, or completely removed by these methods; conversely, there are no data suggesting these methods cannot have any effect on H1N1. However, with long-term nasal washes using Neti pots, sinus infection with other pathogens may be encouraged.
Other investigators and physicians have offered additional methods that may help reduce exposure to H1N1 virus. For example, Dr. Gerberding, a former CDC director, had several suggestions about how to avoid H1N1 infection on an airplane. She suggested the following:
1. If a person is next to you or near (within 6 feet) and is coughing/sneezing, ask the flight attendant to offer the person a mask.
2. If there are available seats 6 feet or more away from the coughing/sneezing person, ask to change your seat (planes are good means of travel because the air is recirculated through HEPA filters that can capture viruses, but even the filters will not help if people touch areas where droplets have landed; HEPA filters are usually not available in buses, cars, ships, or trains).
3. Turn away from the coughing/sneezing person and turn the air vent toward the person to blow the droplets away from yourself.
Variations of her suggestions may be applicable in many different social or work, or travel situations, but there are no data to prove these methods are effective. In addition, common-sense precautions such as not drinking or eating things touched by others, avoiding casual physical contacts (for example, handshakes, social hugs or kisses, public water fountains [these are OK if you touch nothing and lips only touch flowing water], banisters on stairways, and restroom door handles) will limit exposure to H1N1 and other viruses. Again, these common-sense suggestions lack data substantiation.
Many investigators suggest that people stay well hydrated, take vitamins, and get plenty of rest, but these precautions will not prevent H1N1 or other viral infections, although they may help reduce the effects of infection by strengthening the person's immune system to fight infection. Similarly, current antiviral medications (described in the preceding section) act on H1N1 and other viruses that have already infected cells; they work by preventing or reducing viral particles from aggregating and being released from infected cells. Timing is important; if only a few cells are infected and the antiviral medications are administered quickly (usually before flu symptoms develop or within 48 hours), the viruses are reduced in number (they cannot easily bud out from the cell surface), so few, if any, other respiratory or mucus membrane cells become infected. This can result in either no flu symptoms or, if a larger number of cells were initially infected, less severe symptoms. The overall effect for the person is that the H1N1 or other viral infection was prevented (it was not; the symptoms were prevented from developing) or that symptoms were reduced.
There are many flu "cures" and "treatments" listed in the Internet (for example, how cayenne pepper can be used to treat the flu); before using any of these substances, check with your doctor.
In the strictest sense of the word prevention, even effective vaccines do not "prevent" infections. What they do accomplish is to alert the immune system to be on guard for certain antigens that are associated with a specific disease-causing agent (for example, H1N1 virus, pneumococcal bacteria). When the agent first infects the host, its antigens are recognized, and these cause a rapid immune response to occur that prevents the pathogen from spreading and developing symptoms in the host. People, including physicians and researchers, often term this complex response to vaccination as "prevention of infection," but what actually occurs is the prevention of further infection so well that symptoms do not develop or are minimal in the host.
In summary, if H1N1 or other viruses fail to contact cells they can infect, the disease will be prevented. As stated above, this is difficult, but not impossible, to do in almost all societies. Prevention of flu symptoms of infection is possible with antiviral medications if these are given very early in the infection. There are many other methods that may reduce the chance of getting the virus on a person's mucosal surface, but most methods have not been backed up with objective data. Most doctors and investigators suggest that items that help boost or allow the immune response to function well will help people resist H1N1 and other viral infections and reduce symptoms, but these also do not prevent infections. Consequently, while waiting for a specific antiviral vaccine to be developed or become available, there are some ways individuals can improve their chances of preventing or reducing the symptoms of flu virus infections. All of these suggestions apply to H3N2v-caused swine flu as well.