Is It OK to Get a Flu Shot While Sick

Flu shots are very effective at preventing influenza (influenza A virus) infection. They work by stimulating your immune system to produce antibodies against the influenza viruses in circulation. These antibodies prevent future infections caused by these same viruses.

There is no evidence that they cause harm to humans or animals, but there is some concern that getting too many may increase the risk of developing complications such as pneumonia, ear problems and even death.

The Centers for Disease Control and Prevention (CDC) recommends that everyone 6 months of age and older get a flu vaccine every year. There is no need to wait until someone gets sick before getting vaccinated. If you think you might catch the flu, then it’s best to get vaccinated now rather than waiting until symptoms appear.

You will be protected from illness and other possible complications associated with influenza even if you do develop one later.

Getting a flu shot while you’re sick is not recommended because it increases your chances of catching the flu. Getting vaccinated while you’re feeling unwell could make things worse. Your doctor can explain how to protect yourself during and after getting a flu shot.

If you don’t feel well enough to get a flu shot, ask your health care provider about another way to protect yourself from influenza infection.

I’ve heard of people getting the flu after they’ve had a flu vaccine.

Is this true?

Yes, it’s possible to get sick a short time after getting a flu vaccine (usually within two weeks). This happens more commonly in people who have a weakened immune system, but even healthy people may get influenza like illnesses from time to time. If you get symptoms, they will most likely be milder than if you had not been vaccinated.

This is because the vaccine does not contain live influenza viruses. The viruses in the vaccine are either killed (inactivated) or other weakened forms that cannot cause illness.

Getting sick after getting vaccinated is extremely rare and those who do become ill usually experience milder symptoms.

If you do feel like you are getting sick, you may want to contact your health care provider to see if a …

It is possible to get a cold from a flu vaccine. This is because the virus used is a killed virus and cannot make you ill, but it can still “shed” and infect other people around you (much like the regular flu). If you do get a cold after your vaccine, it should be a mild one and will probably be over in less than 10 days.

You can also get a sore arm from the shot. This is more common in children who get the shot, as their skin is sensitive. The injection is given in your muscle (called the deltoid region), which can be a little painful.

The soreness will go away in a day or two.

Some people get a headache from the flu vaccine. This can happen, but it’s not common. If you get a headache after getting the vaccine, it should be over in less than 48 hours.

It’s important to keep a record of your recent vaccinations in case you do need medical treatment, your health care provider should be able to tell if you’ve been vaccinated within the last year.

You can also get a mild fever from your vaccine. This happens less than one percent of the time and will only last a day or two. If you do get a fever after getting vaccinated, it should be over in less than 10 days.

In extremely rare cases, some people have had reactions that required them to be hospitalized after getting the vaccine. This is less than one-hundredth of one percent of those vaccinated. If you do feel unwell after getting the vaccine, you should contact a health care provider right away.

Do I need to fast before having the vaccine? Should I eat anything before getting it?

It is not necessary to eat or fast before getting a flu vaccine, unless your doctor tells you to.

How well does the vaccine work?

The vaccine “works” by trying to protect you from influenza illness and complications in the short term and stopping influenza spreading more widely through the community in the longer term. The vaccine does not provide total protection against influenza and it is impossible to predict which flu viruses will be most important in any given season.

The vaccine works better against some strains of influenza than others and it is difficult to make an exact prediction every year. The vaccine protects well against the strains of influenza that are in the vaccine and it also protects against influenza illness even when the vaccine and flu viruses do not match exactly. It takes about two weeks after having the vaccine for it to provide protection.

Many older people do not develop enough immunity to the influenza virus after having the vaccine and still contract the illness. This may be because their immune systems are not as effective as younger people’s. Also, some younger people may not mount a strong immune response to the vaccine, although it is much less likely.

The vaccine also protects against influenza illness even if the vaccine and flu viruses are not an exact match.

Some people say they got influenza after they had been vaccinated. The vaccine is not 100% effective, but it still reduces the risk of influenza. The vaccine also protects against other strains of influenza that you may catch.

The match between the virus in the vaccine and the strains that are spreading in the community changes each year as new viruses are selected for the vaccine. There can also be variability in the vaccine itself from year to year.

How long does the vaccine last?

The vaccine provides protection against influenza for up to a year.

Does the vaccine prevent other strains of influenza in addition to the H1N1 strain that is in the vaccine?

The vaccine doesn’t protect against other strains of influenza in addition to the one that is in the vaccine. As mentioned above, there can be variability in the vaccine itself from year to year.

Should I have a flu vaccine if I’m pregnant?

Yes, you should have a flu vaccine if you are pregnant regardless of your risk category. Every year in Canada, hundreds of pregnant women get influenza and are at risk of developing complications that could affect their own health and that of their unborn child. Getting the vaccine will reduce the risk of these complications occurring.

Does everyone over the age of six months need to get the H1N1 vaccine when it becomes available?

In a pandemic, authorities may recommend that people in certain “at risk” groups should receive the vaccine first. This is because limited quantities of the vaccine are expected to be available at the beginning of a pandemic and it will take time to increase production. It is also important to protect those who are at high risk of complications due to influenza as soon as possible.

When more vaccine is available, authorities will then recommend that people in the other risk categories receive it.

As an individual, you can also decide to get the vaccine even if you are not in one of the recommended risk categories.

What are the pandemic classification criteria?

Health Canada has developed a set of criteria that will be used to determine when a novel influenza virus has achieved pandemic status. The World Health Organization makes this determination for the rest of the world.

The criteria include:

whether or not there is evidence of person-to-person spread of the virus;

the presence of a potential vaccine and the timely availability of protective masks; and,

the extent of disease spread.

The decision to declare a pandemic is made by the World Health Organization.

Is it too late to get the vaccine now? Won’t we have a stockpile because the vaccine has been developed?

It is never too late to receive the vaccine. Even if there is a stockpile of vaccine in Canada, it may not be readily available to everyone. If there is a pandemic, a limited amount of vaccine will be available at the beginning to protect people who are at high risk of developing complications from influenza. It will take time to produce more vaccine.

Where can I get a vaccine?

The vaccine will not be available everywhere. Your doctor or local public health unit will be able to provide more information on where your closest place to get the vaccine is located.

What if I don’t want to get the H1N1 vaccine?

You do not have to get the vaccine if you do not wish to do so.

Why are we being told to wear masks if the vaccine isn’t effective?

There are two reasons for this: to prevent you from getting sick and to prevent you from spreading the virus to others. Even though the vaccine may not protect everyone, it will still reduce the chance of getting influenza. If you are sick you are more likely to give the virus to someone else without taking the proper precautions such as regularly washing your hands and wearing a mask.

Is it still a good idea to wash my hands when I have a cold or feel one coming on?

Yes, it is still very important, because if you do not have a flu virus you can’t spread it to someone else. It also reduces your chances of getting other types of infections.

Influenza is spread mainly by droplets that are emitted when an infected person coughs, sneezes or talks. These droplets can land on surfaces such as doorknobs, tabletops and other areas where the droplets can survive for several hours. They can also be inhaled by people nearby.

The virus can also be spread through personal contact. For example, if someone touches a surface where the virus is present and then touches their eyes, nose or mouth before washing their hands the virus can enter the body this way.

What are the signs and symptoms of influenza?

The onset of influenza is usually abrupt and the illness can be misdiagnosed as a simple cold for a few days. The most common symptoms of influenza are:



muscle aches;


cough; and,


These symptoms often develop within a few hours after exposure to the virus and can last for several days. Most people will begin to feel better after two weeks although tiredness may linger for a month or longer. In some people however the disease is so severe that they require hospitalization and even intensive care.

Who is at risk of developing complications from influenza?

Influenza can be a serious illness in people with chronic medical conditions such as heart or lung disease, diabetes, or in people who have an impaired immune system. Pregnant women, children and teenagers are also more likely to develop complications from influenza than healthy adults. If you fall into one of these risk groups it is important that you see a doctor if you think you are coming down with the flu.

How is influenza treated?

Treatment is focused on relieving the symptoms such as pain, fever and aches. Aspirin or other painkillers are recommended for treating high temperature. Antibiotics are not effective against viruses so they are not prescribed for treating influenza. Drinking plenty of water and juice will help prevent dehydration caused by fever and helps relieve headaches. Aspirin or acetaminophen can be taken to relieve headache.

How can I avoid getting influenza?

The best way to avoid influenza is to get the vaccine each year as prescribed by your doctor. The vaccine is free of charge for people at high risk of developing the complications listed above. Getting the vaccine not only protects you from getting influenza but also protects others around you who may be more vulnerable. The vaccine takes about two weeks to take effect so it is important to get it before the flu season begins which usually occurs in the fall.

How can I protect myself and others from influenza?

You should:

Wash your hands frequently. Alcohol based hand sanitizers are an effective substitute for hand washing when water is not available. Be sure to use soap and water as soon as possible if you don’t have access to a hand sanitizer.

Don’t touch your eyes, nose or mouth. Germs spread this way.

Try to avoid people who are sick.

Avoid close contact with sick people.

Try to avoid crowds when possible.

You should also consider the following if you have a compromised immune system:

Do not visit people in hospitals or nursing homes. You are more susceptible to catching other infectious diseases that are rampant in these type of facilities.

Do not handle food for other people. You run the risk of getting sick from others and you might unknowingly contaminate the food you are preparing.

Do not attend public events when possible. You are around a lot of people which increases your risk of getting sick.

What about the swine flu?

The swine flu is a respiratory illness that affects pigs and can infect people. It probably causes a milder illness in people than seasonal influenza and it is treated with the same medications. Most healthy people will recover with no complications.

The current outbreak of “swine flu” is a new strain of influenza A virus subtype H1N1. It causes a respiratory illness, which is similar to other seasonal flu strains such as:

There have not been any confirmed cases of swine flu resulting in death and there have only been a few confirmed cases at this time. The state department of health is working with the CDC and local doctors to identify and confirm cases.

Swine flu is spread through objects that people touch after they have touched their nose or throat, or objects that have been in contact with infected fluids. You can also get the virus from the respiratory secretions of someone who is sick with swine flu. You cannot get it from properly cooked pork.

The best way to avoid getting the infection is to practice good handwashing. Avoiding people who are coughing and sneezing and staying home if you are sick also helps prevent the spread of this virus.

Swine flu can be confirmed with a flu test, which will identify antibodies for the H1N1 virus in your blood. Treatment is the same as for other flu strains and may include the prescription drugs oseltamivir (brand name Tamiflu) or zanamivir (brand name Relenza). Both drugs work to prevent the virus from making you sick or reduce your symptoms.

They will not make the virus go away and people who have had swine flu have still remained sick even while taking these drugs.

Swine flu is a respiratory illness that can be spread between people. It is caused by the influenza A virus that has different subtypes. The current swine flu outbreak is caused by a new subtype called H1N1.

This virus may have originated in pigs and then mutated to infect people. (source)

The symptoms of swine flu include:

A low fever that is generally lower than 101 degrees


muscle aches

runny nose

throat irritation

nausea and vomiting

Diarrhea is also common with this virus. It usually is not spread as easily as the common cold. It takes close contact with an infected person for several hours before the virus can be transmitted.

It is most commonly spread in hospitals and schools, so it is harder to catch than a cold.

Although Tamiflu and Relenza can reduce your symptoms they cannot make the virus go away. The viruses effects will still be there as soon as the drugs have worn off. (source)

As with most viruses, getting enough rest and drinking adequate liquids is the best way to get over this quickly.

The current swine flu vaccine is only 10% effective so it is not recommended that you get it. (source)

We asked the CDC if they had any other recommendations and they told us:

“The most important thing everyone can do is to practice good respiratory and hand hygiene. Please wash your hands frequently with soap and water, especially after coughing or sneezing. If soap and water are not available, use an alcohol-based hand rub.”

Exactly what good is a vaccine if you are supposed to wash your hands anyway?

Maybe this one is different.

I think I will wait to see if they come out with a new one that is more effective.

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THIS concludes today’s post!

Thanks again for tuning in folks and be sure to tune in next Friday, when I will be posting the first of my special blogs that I promised you all!

Happy weekend!


Current Mood: accomplished

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Sources & references used in this article:

Swine flu: A field study of self‐serving biases by L Larwood – Journal of Applied Social Psychology, 1978 – Wiley Online Library

The Flu Shot and the Egg by LK Boerner – ACS Central Science, 2020 –

How can you improve vaccination rates among older African Americans? Patients want you to address their fear of drug interactions and allergic reactions by RJ Wray, K Jupka, W Ross, D Dotson… – Journal of Family …, 2007 –

The Flu Shot and the Egg by L Krietsch Boerner – 2020 – ACS Publications

How to talk to reluctant patients about the flu shot by CT Fogarty, LT Crues – Family Practice Management, 2017 –

What is “the Flu”? by M Sockrider – American journal of respiratory and critical care …, 2020 –

The Flu Shot and the Egg by LK Boerner –

Information from your family doctor: Influenza vaccine by C Brooks – American Family Physician, 1999 –

How Effective Is the Flu Shot, Anyway? by V Goldschmidt –