Dog Vaccine Side Effects And Safety

labrador puppy getting first vaccination

Dog vaccine safety is something that many pet parents are concerned about. Vaccinating a dog is an expensive business, but are you putting your Labrador at risk if you don’t vaccinate? And are you putting him at risk if you do?

We answer your concerns about the safety of vaccination, look at the risks of side-effects and help you choose the right path for you and your puppy.

If you want to jump to particular questions just use the green menu to the right.

You’ll find a couple of links to related articles at the bottom. Don’t forget to drop your comments or questions in the comments box below!

A more dangerous time for puppies

Fifty or sixty years ago nasty and fatal infectious diseases were a common cause of death in all dogs,  especially in small puppies.

When I was very little, our pet dog Tim caught distemper and nearly died.

My mother nursed him through the illness but he never fully recovered and was eventually put to sleep as a result.

Vaccinating puppies became routine in most parts of the Western World during the 1960s and 70s.

People were relieved to be free from worry about distemper and other serious infections.

Nowadays, in Europe and North America at least, and almost certainly as a result of widespread vaccination, dog’s lives are rarely ruined by distemper or other horrible diseases.

However, some dog owners have now begun questioning the safety of vaccinations and rates of vaccination are falling in some areas.

Do puppy vaccinations have side effects

The effect we want from vaccination is of course protection from disease.

And modern puppy and dog vaccinations do a good job.

Like most effective medical treatments, most vaccinations do have recorded side effects.

Find out just how safe puppy vaccinations really are

These are well documented and several studies have been done looking at vaccination side effects, and at which dogs were most likely to be affected

Are vaccination side effects serious?

Thankfully serious side effects from puppy vaccinations are rare

Although this is no consolation to anyone whose dog is affected.

Most side effects are mild and pass off within a day or two.

More common side effects are a puppy feeling a bit ‘off-colour’.

Or a little lump developing at the injection site.

Keeping an eye on your puppy

To be on the safe side keep an eye on your recently vaccinated Labrador puppy.
He may lose his appetite and be less lively than normal.

If he hasn’t perked up and started eating enthusiastically again within 24 to 36 hours,  give your vet a ring and let him know what the situation is.

Likewise,  if he seems more than just a little off-colour,  it is best to check with your vet.

Watching out for lumps

Sometimes a lump develops at the site of the injection.

Let your vet know if the lump looks sore, or if it hurts your puppy when you touch it, or if it gets much bigger than pea sized,  or if it is still there after a few weeks.

It may mean nothing at all,  but your vet needs to know so that he can check the skin has not become infected.

So are puppy vaccinations safe?

We do know that  some dogs will react to a vaccination, and that in a very few cases that reaction will be serious.

Very occasionally a previously healthy dog may die. Which is of course an absolute tragedy. And one you are highly likely to hear about.

However, studies show that overall, vaccinations are currently extremely safe.

A large study of over four thousand dogs found no link at all between the time period following vaccination, and illness in the vaccinated dog.

Another study  looked at adverse event within 3 days of vaccination. This study of 1.2 million dogs showed an incidence of 3.8 reactions per thousand dogs (around three thousand doses of vaccine). This included mild reactions.

The fact is, that taken over the population as a whole, vaccines are relatively safe. And all the millions of puppies that are vaccinated safely each year go quietly home and never hit the headlines.

Why do unvaccinated dogs not get sick

So, if vaccines are meant to protect against all these awful diseases, why is it that unvaccinated dogs all seem to be fine?

You will almost certainly know someone that does not vaccinate their dogs.

When my husband and I were first married and were struggling financially,  we did not vaccinate any of our dogs for several years. We were lucky and they survived.

In the UK and elsewhere there are of course many unvaccinated dogs surviving today too.

So why is it that we are all urged to vaccinate our pets if many unvaccinated dogs manage to breeze through life without so much as a day’s illness.

Are we just lining the pockets of our vets while all around we hear reports of vaccine damage, and the dangers of over-vaccination?  Let’s have a look.

What is herd immunity?

The reason that unvaccinated dogs survive without catching distemper, parvovirus or other horrible and often fatal diseases is herd immunity.

When a high proportion of individuals in any given population are vaccinated,  those that remain unvaccinated are protected by the widespread immunity within the community.

Sufficient people do vaccinate their dogs to make it relatively unlikely that your dog will meet a very sick one.

The reason my own dogs survived unvaccinated all those years ago,  was because most of the dogs they met were vaccinated.

In other words, if your dog survives without vaccination, you have your friends and neighbours to thank.

It is their commitment to vaccinating their dogs which helps to keep your dog safe and sound.

Can I choose not to vaccinate my puppy?

Depending on where you live, some vaccinations may be compulsory, other are not.

In the UK, no puppy vaccines are compulsory, though you’ll need them for travel or boarding purposes.

In countries where dogs carry diseases transmissible to humans, rabies for example, you are often obliged by law to vaccinate your puppy – for the protection of the human as well as the canine population

The risks to dogs of not vaccinating

If you decide not to vaccinate your puppy, you will be dependent on herd immunity and luck for your dog’s protection. Diseases  like the distemper that killed my childhood friend have not been completely eradicated yet.

Don’t forget that some diseases are not just contracted from other dogs.  Leptospirosis for example can be transmitted through the urine of rats and other wild animals and caught from contaminated water.  And we all know how Labradors love to swim.

Bear in mind also,  that whilst diseases like distemper are relatively rare in the UK, parvovirus  is not.

Every year there are outbreaks of parvo in various locations,  and whilst adult dogs sometimes survive this horrible virus,  it is often fatal in puppies.

Outbreaks of disease

The problem with relying on herd immunity is that when the proportion of vaccinated individuals  in the community falls below a certain level, herd immunity breaks down and disease breaks out.

And it is difficult to define or predict this level or to know when it has been breached.

There are still regular outbreaks of diseases that vaccines protect against, not only in the USA and the UK where most of our readers live, but elsewhere too.

Whilst the risk of contracting a disease in lower when herd immunity is high,  these are very serious diseases. The risk of death should your puppy be infected, is high.

How many puppies need to be vaccinated?

We do not know how many puppies need to be vaccinated to keep herd immunity high.

But we do know that the number of unvaccinated individuals needs to remain a fairly small proportion of the population in order to prevent epidemics of diseases like distemper reappearing.

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So who should those individuals be?

Protecting the vulnerable

Some dogs really should not be vaccinated.

This includes dogs that are sick, dogs that have had a bad reaction to a previous vaccination, or puppies that are too young for the vaccination to work.

To protect these vulnerable individuals, we need to maintain a strong herd immunity. And that is down to the rest of us

In addition, we may be able to reduce the slightly increased vulnerability of some dogs to vaccines by altering the way in which shots are scheduled for these particular individuals

Dog size and vaccination frequency

When we look more closely at the risks involved in vaccinating our dogs, these risks increased for smaller dogs, with increasing age, and where multiple vaccinations were given at a single appointment.

The risks were lower for larger dogs like Labradors, and for puppies under a year old.

In addition, many vets are now offering a vaccination programme which reduces the vaccine load on each individual dog. And owners of small breed dogs should discuss spacing out the shots for their dogs, particularly as they get older.

Several of the vaccines in current use have been found to be effective for far longer than one year, and revaccinations are now being adjusted accordingly.


There is no doubt that immunity for some of the diseases that we vaccinate dogs against, lasts far more than a year.  Many people, veterinarians included, are concerned about the effects of repeatedly vaccinating dogs on a yearly basis

In some cases core vaccinations may even last for the dog’s lifetime.  This means that if a dog is vaccinated against every disease every year, he is  receiving more vaccine than he needs.
And there are two ways of dealing with this problem
• Variable vaccine schedules
• Titres

Variable vaccine schedules

At one time, all dogs got every shot going, each year on an annual basis.  This is changing

Some vets will vaccinate every year against some diseases, and less often against others.  This is called a variable vaccination schedule and current thinking is that this is much better for your dog

A few vets still seem to insist on the dog getting the whole dose every year. But variable vaccination schedules are now becoming more common.

There is another option, and that is to test your dog for immunity before vaccinating him.

This is where titers come in.


It is possible for your vet to take a blood sample from your dog and actually check his immunity.

This blood test is called a titer.  It looks for antibodies in the blood sample.   These antibodies are specific for each different disease.

In theory the results of the titer then enable you to have your dog vaccinated, only against those diseases that he has reduced immunity to.   In practice,  low antibodies in a titer are not the whole story.

Immunity is more complex.   You can read some interesting information by Vet Janet Crosby  on this subject at if you are thinking of having your dog titer tested.

Because of concerns over vaccine safety and over-vaccination, some people have looked for alternative treatments such as homeopathic nosodes.

What about homeopathic nosodes?

Unfortunately, there is no evidence to support the beliefs that homeopathic nosodes can be relied upon to keep your puppy safe.

On the contrary, in-depth enquiries commissioned by the British and Australian governments looking at hundreds of clinical trials, found all homeopathic treatments to be no more effective than a placebo

And in a study carried out by Larson, Wynn and Schulz,  all the puppies that they  ‘vaccinated’  with homeopathic nosodes died when exposed to parvovirus.

In another study,  only one in five puppies survived.

So basically, if you use nosodes, your puppy is as unprotected as if you didn’t vaccinate at all.

Dog vaccine side effects – your options

In most states in the USA rabies vaccination is required by law, but vaccinating against the other serious core canine infectious diseases is left up to the conscience of the dog owner.

Many studies have shown that the benefits of vaccination outweigh the risks. Adverse effects are mostly minor and tragic reactions are rare.

If you have a choice over whether or not to vaccinate your dog you will need to decide where your priorities lie.

You could decide to rely on herd immunity and leave the responsibility for that with your friends and neighbours. It’s an option, though not one we would recommend.

Few people would contest the sense in vaccinating a puppy, especially as the evidence suggests that the risk to Labrador puppies under a year old is even less than the small risk to dogs of all ages and sizes as a whole.

Do talk to your vet, he or she will have an interest in the latest research on this important subject and veterinary science is a rapidly developing field.

On a personal note I believe that it is important to keep the general dog community free of these horrible diseases,  to vaccinate young puppies for their own safety. And to protect our human friends from diseases that can be passed on from our pets.

Even if you live in a region where vaccinating pets is not a legal obligation, vaccination is important if puppies are to be able to go about in society and be properly socialised at a young age.

 To me, this is more important than the small risk to my individual dogs of vaccination side effects.

Dog vaccine safety – a summary

Vaccinations have saved millions of dogs lives and continue to do so. They are arguably the most significant influence on improving canine health in the last hundred years.

They are not perfect, but it is frighteningly easy to throw the baby out with the bath water.

It is easy to forget how terrible the diseases we see so rarely actually were. Or how vulnerable the next tiny puppy you bring home will be if your friends do not vaccinate their dogs.

Vaccination at the moment, in our herd immunity protected world is to some extent an act of altruism. It is possible that your dog will not come to any harm if you leave him unvaccinated,  (there is also a  risk he will get sick).

What we do know is most dogs will not experience any serious side effects from a sensible programme of vaccination.  Quite aside from the evidence to support this, it may be of some comfort for you to know that in the thirty years or so that I have been vaccinating my own (several) dogs, I have never seen a vaccine reaction.

Best of all, we know for certain, that vaccinating your puppy will most definitely benefit all the other dogs he comes into contact with, including every other vulnerable new puppy within your community.

As a result, I would recommend any new puppy owner to have their dog vaccinated,  Both for their own protection and for the protection of puppies everywhere.

What do you think?  Should we vaccinate our puppies?  What did you decide to do?

More information on puppies

Happy-Puppy-jacket-image1-195x300For a complete guide to raising a healthy and happy puppy don’t miss The Happy Puppy Handbook.

The Happy Puppy Handbook covers every aspect of life with a small puppy.

The Labrador Handbook by Pippa Mattinson

The book will help you prepare your home for the new arrival, and get your puppy off to a great start with potty training, socialisation and early obedience.

The Happy Puppy Handbook is available worldwide.

You might also find it useful to read – when can I take my puppy out – which looks at ensuring the safety of your puppy before his vaccination cover is complete

Below are some of the sources of information discussed in this artice, and some studies and reports on canine vaccination that you might find interesting

References and further reading

Day M J. Vaccine side effects: Fact and fiction. Veterinary Microbiology 2006
Horzinek M. Vaccine use and disease prevalence in dogs and cats Veterinary Microbiology 2006 

Thiry E, Horzinek M. Vaccination guidelines: a bridge between official
requirements and the daily use of vaccines Veterinary Sciences Tomorrow (pdf) Riedl et al. Prevalence of antibodies to canine parvovirus and reaction to vaccination in client-owned, healthy dogs. Veterinary record 2015

Poulet H. Alternative early life vaccination programs for companion animals. J Comp Pathology 2007. 

Cleveland et al. Canine vaccination—Providing broader benefits for disease control. Veterinary Microbiology. 

Fekadu M et al. Immunogenicity, efficacy and safety of an oral rabies vaccine (SAG-2) in dogs. Vaccine 1996. 

Moore G et al. Adverse events diagnosed within three days of vaccine administration in dogs. Journal of the American Veterinary Medical Association 2005. 

Meyer K. Vaccine Associated Adverse Events. Vet Clinics of North America Small Animal Practice 2001. 

Chalmers W. Overview of new vaccines and technologies. Veterinary Microbiology 2006. 

The Labrador Site Founder

Pippa Mattinson is the best selling author of The Happy Puppy Handbook, the Labrador Handbook, Choosing The Perfect Puppy, and Total Recall.

She is also the founder of the Gundog Trust and the Dogsnet Online Training Program 

Pippa's online training courses were launched in 2019 and you can find the latest course dates on the Dogsnet website

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Pippa Mattinson is the best selling author of several books on dogs. She is the founder of the Labrador Site and a regular contributor. She is passionate about helping people enjoy their Labradors and lives in Hampshire with her husband and four dogs.


  1. I appreciate what you said about side effects from puppy vaccinations being a rare occurrence. I think that dog vaccinations are critical to the health and wellbeing of any animal. My wife and I have a cocker spaniel that we recently adopted, so we’ll be sure to get in contact with the best vet in our community to provide all the necessary dog vaccines to our angel.

  2. My Labrador is one of the tiny minority of dogs who experienced serious side effects. An immune response to the first puppy vaccination hospitalised him for seven weeks and it was a while after that before he could stand unaided. He has lifelong soft tissue and bone abnormalities as side effects of the Acute Polyradiculoneuritis. Regardless, I would still vaccinate another dog. An unvaccinated dog is ineligible for kennels and group obedience classes.

  3. My 3month golden Labrador has been diagnosed with distemper.I had vaccinated him at 2 months but still she got the horrible disease. She was jolly and play full but just after vaccinating she stated loosing balance and unable to has given medicines but nit sure if it can b cure.pls pray for her.