Facts on Viral Pneumonia
Pneumonia is an infection or inflammation of the lungs. It can be in just one part of the lungs, or it can involve many parts. Pneumonia is caused by bacteria, viruses, fungi, and other microorganisms. The severity of pneumonia depends on which organism is causing the infection and the immune response of the individual to that infection. Viral pneumonias are usually not very serious, but they can be life-threatening in very old and very young patients and in people whose immune systems are weak.
Two of the most publicized viral infections causing pneumonia are SARS and H1N1 swine flu. Severe acute respiratory syndrome (SARS), which is caused by a virus in the coronavirus family, had a major outbreak in 2003 with an estimated 8,000 cases and 750 deaths. For the latest information on this illness, visit the Centers for Disease Control and Prevention web site.
Swine flu (H1N1) was associated with an outbreak of pneumonia in 2009. Early reports came from cases in Mexico, with a very high mortality. Many cases were also reported in the U.S. However, early identification and treatment helped reduce the death rate significantly.
Viral Pneumonia Causes
Viral pneumonia can be caused by influenza virus, respiratory syncytial virus (RSV), and the herpes or varicella viruses as well as those that cause the common cold (parainfluenza, coronaviruses, and adenoviruses).
Depending on which virus is involved, the symptoms and severity and treatment varies.
Influenza A and B usually occur in the winter and spring. In addition to the respiratory symptoms, you can get headache, fever, and muscle aches. Your chance of catching the flu decreases significantly (but is not totally prevented) if you get immunized ("flu shot") every year.
Respiratory syncytial virus (RSV) is most common in the spring. It usually infects children and can cause outbreaks in day-care centers and hospital nurseries.
Herpes, or varicella, pneumonia is rare unless you are infected with chickenpox. This tends to be a more common complication in adults who get chickenpox.
Adenovirus and parainfluenza viral pneumonias are often accompanied by cold symptoms such as runny nose and pinkeye (conjunctivitis).
Viral Pneumonia Symptoms
Most viral pneumonias have the following symptoms in common:
Low-grade fever (less than 102 F)
Coughing up small amounts of mucus
Symptoms of pneumonia caused by a virus
other than influenza usually go on for several days to a few weeks before you call your doctor. Most people with bacterial pneumonia
and influenza get sick very quickly and see a doctor within a few days.
When to Seek Medical Care for Viral Pneumonia
Go to your hospital's emergency department or call your doctor if you develop any of these symptoms:
- Persistent cough
- Shortness of breath, either at rest or with just a little exertion
- Severe chest pain
- Severe weakness
- Coughing up blood
- Vomiting so much that you are dehydrated
- Unable to take in food and fluids
Viral Pneumonia Diagnosis
Your doctor will check your temperature, heart rate, and blood pressure.
A pulse oximeter (a small clamp-like device, which looks like a clothespin)
may be put on your finger to check your blood oxygen level. Your doctor will examine you and specifically listen to your heart and lungs to help determine the cause of your symptoms and the severity of your illness. If it is possible that you have pneumonia, you will probably have an X-ray of your chest.
- Influenza A and B are usually diagnosed clinically, which means the symptoms give the diagnosis. Often screening lab tests can help with the diagnosis. These tests are usually taken from secretions from your nose to help identify the organism.
Varicella pneumonia is usually diagnosed clinically because it usually happens during an outbreak of the chickenpox. The chest X-ray is often characteristic after the infection has resolved (small round white dots seen in both lung fields).
If your doctor suspects respiratory syncytial virus (RSV), a swab of your nose secretions can be sent for testing by a laboratory. Children and infants are more likely to be tested for RSV, because this virus can be more serious in them.
Adenovirus and parainfluenza virus are not likely to cause life-threatening illness. Tests are rarely done if these viruses are suspected to be the cause of pneumonia.
How to Prevent the Common Cold
Viral Pneumonia Home Remedies
If you've been diagnosed with viral pneumonia, you need to rest and drink plenty of fluids.
If you overexert yourself when you are sick, even with a virus, you can prevent your immune system from fighting off the illness, and possibly get even sicker.
You can use over-the-counter medicines to reduce fever, body aches, and cough. Although some medicines can help you feel better, you still need rest. These medicines won't cure you, and your body still needs rest to have the energy to fight the infection and to heal itself.
Viral Pneumonia Treatment
If you are diagnosed with a viral pneumonia, an antibiotic will not help you get better faster. Antibiotics work only on illnesses caused by bacteria. Your best treatment is to rest and keep yourself hydrated. But there are some bacteria that do not behave like standard bacteria when they cause pneumonia. These are referred to as atypical infections with organisms like Mycoplasma, Legionella, and Chlamydia. These infections do respond to antibiotics. So if your physician is not certain if your infection is viral or due to one of these atypical bacteria, an antibiotic may be prescribed to cover these atypical organisms.
- If your doctor suspects your pneumonia is caused by an influenza virus, you may get a prescription for an anti-flu medicine. It must be started within 36 hours of the beginning of symptoms to be effective. Four drugs are available: Amantadine (Symadine, Symmetrel), rimantadine (Flumadine), and oseltamivir (Tamiflu) are pills or capsules. Zanamivir (Relenza) is a powder that you inhale directly into your lungs.
- Varicella pneumonia is almost always serious enough to need treatment with acyclovir (Zovirax) or a similar antibiotic. You can take this drug by mouth or, if you are severely ill and in the hospital, by IV.
- Respiratory syncytial virus usually needs treatment for symptoms only. If you are sick enough to be in the hospital, you might be treated with ribavirin (Rebetol).
- Treatment of adenovirus and parainfluenza virus pneumonia is also just to relieve symptoms.
Follow-up for Viral Pneumonia
- If you are treated at home, your doctor will probably ask you to return in one to four weeks to be checked.
- You may need a repeat chest X-ray when your symptoms have improved. Because some types of pneumonia can look like cancer, a second X-ray will prove that it is not.
Viral Pneumonia Prevention
Germs are spread both by aerosolized droplets that you breathe in (such as from a sneeze) and through body fluids left on surfaces like countertops and door handles. If you avoid people who are coughing or sneezing, and wash your hands frequently, you can reduce your chances of catching a virus.
Fluids and rest during bouts of the common cold can help prevent progression to pneumonia.
If you get a flu shot every fall, you reduce your chances of getting influenza pneumonia.
If you have never had chickenpox, you can get a vaccine to prevent it. You should discuss with your health care professional if the vaccine is indicated for you.
Viral Pneumonia Prognosis
Most people get well quickly with no damage to the lungs. You are at a greater risk for developing complications if you are very old or very young, or if you have a weakened immune system, or if you have chronic heart or lung disease.
Reviewed on 10/19/2018
Medically reviewed by Robert Cox, MD; American Board of Internal Medicine with subspecialty in Infectious Disease
McIntosh, K., and S. Perlman. "Coronaviruses including severe acute respiratory distress syndrome (SARS)-associated coronavirus." In: Mandell, G.L., Bennett, J.E., Dolin, R., eds.
Mandell, Douglas, and Bennett's Principles and Practice of Infectious Disease. 7th ed. Philadelphia, Pa: Saunders Elsevier, 2009: chap 155.
Perez-Padilla, R., et al. "Pneumonia and Respiratory Failure from Swine-Origin Influenza A (H1N1) in Mexico."
NEJM 361 (2009): 680-689.