It's not the flu. 

The flu vaccine doesn't protect you.

Parainfluenza viruses are different from influenza.

The parainfluenza viruses are actually 4 viruses HPIV-1, HPIV-2, HPIV-3, and HPIV-4.

Oddly enough this virus spreads more in odd numbered years, like 2015 and 2017.

Who gets these?

All of us do. Mostly children are infected.

Most children by age 5 have had HPIV-3 and have the antibodies to prove it.

3 in 4 will have antibodies against HPIV-1 and HPIV-2.

The elderly are also particularly susceptible and can have more severe infections. Those who are reinfected as adults usually just have a cold, but some can have pneumonia, bronchitis, or bronchiolitis (inflammation of the bronchioles, smallest airways in the lungs, which is usually seen in infants and can cause wheezing and shortness of breath).

What do they cause?

Each type is associated with a slightly different illness.

HPIV-1 causes the croup. The croup (laryngotracheobronchitis) is often caused by a viral infection (like HPIV) an causes swelling in the the throat which can lead to a problems breathing (as if trying to breathe through a small straw), a barking cough, and a hoarse voice. HPIV-1 can also cause colds and lower respiratory tract illnesses (bronchitis, bronchiolitis, pneumonia).

HPIV-2 causes the croup, but is less common.

It can also cause colds and lower tract infections.

HPIV-3 is more associated with bronchiolitis, bronchitis, and pneumonia.

HPIV-4 is the least common, but can cause respiratory illness. There is both a 4a and 4b.

Can you be infected more than once?


How do you catch this?

Usually infection develops 2 to 7 days after exposure to someone who is sick.

Those who are most contagious are those in the early stages of infection.

It is spread when someone coughs or sneezes in the air and infectious droplets are released into the air. Others may breathe these in. These droplets may also land on surfaces, which others may touch before touching their own faces, which then infects them. Infections can also spread by shaking hands or touching. Objects can be contaminated by the virus - such as doorknobs or countertops - after being touched by someone who is infected. Those who touch these surfaces may infect themselves by touching their face (mouth, nose, or eyes).

When can you catch this?

Interestingly there are seasons for parainfluenza.

HPIV-1 occurs in the fall, usually in odd-numbered years. more cases in the fall of odd-numbered years.

HPIV-2 occurs more commonly in the fall and is less common than types 1 or 3.

HPIV-3 is usually found in the spring and early summer, but it occurs year round, especially 1 and 2 are not occurring. 

HPIV-4 is less well tracked and its seasons are not as well known.

How do you avoid the infection spreading?

Wash your hands well. This avoids you spreading infection and keeps you from being infected. If possible, do not stand immediately in front of someone who is coughing or sneezing. Many respiratory viruses do not spread more than 3-6 feet in the air. Make sure anyone who coughs or sneezes covers their mouth with a tissue or their elbow or upper sleeve. The tissue should be thrown away immediately.

Is there a vaccine?

Unfortunately, no.

Is there specific treatment?

Nope. If there is no additional bacterial superinfection, antibiotics also will not help.

How do you find out if you are infected?

There are lab tests that can be performed on respiratory secretions or nasal swabs. These are special PCR tests that can look for a variety of respiratory viruses. However, these tests are often not available and are expensive. As there is not a specific treatment for parainfluenza, a specific diagnosis will not usually change treatment.

Some labs perform immunofluorescence testing on respiratory samples. Others might test for changes in antibody levels with infection.

What sort of virus are parainfluenza viruses?

They are Paramyxoviruses. Other members of this virus family include hMPV, Measles, and Mumps.

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