Titers, Nomographs, and Smarter Pet Vaccination

Protecting Without Over-Vaccinating

By ANDREA CARLSON DVM BS CVFT CVCH CVA CVTP CVTPEP CTCVMP CVMMP CVMRT

Every year, countless dogs and cats receive routine booster shots — even though many of them are already fully protected. Science tells us that for certain core vaccines, immunity can last for many years, even for life. Yet outdated “one-size-fits-all” vaccination schedules often lead to unnecessary injections. That’s where titer testing and nomographs come in: tools that help scientifically tailor vaccines to the individual pet, improving safety without compromising protection.

What Exactly Is a Titer?

A titer (pronounced “tight-er”) is a laboratory measurement of how much a blood sample can be diluted before it loses the ability to neutralize a virus.  “This testing method is not just theoretical; it is a hands-on, functional, scientific approach used to assess immune status.” Dr. Laurie Larson U of W.    In veterinary medicine, titers are used to measure antibodies against core viruses in dogs and cats — such as canine distemper, parvovirus, adenovirus, feline panleukopenia, and rabies.

High titers typically mean your pet’s immune system is primed and ready to fight off infection. Low or negative titers can mean it’s time for a booster.

A key aspect around vaccinations is understanding that not all vaccines provide the same level of protection.  Unlike core vaccines which typically provide long lasting (8 years via multiple studies) and often lifelong immunity, many non-core vaccines (such as Bordetella, Lyme, or Leptospira-bacterial diseases) don’t produce sterilizing immunity — they may reduce disease severity rather than prevent infection. That’s why titer testing is primarily used for core viral diseases and why at my practice, we do not recommend vaccinating for these bacterial diseases.

Why Titers Matter

Titer testing offers a way to verify immunity without guessing or over-vaccinating. 

Benefits include:

• Avoiding unnecessary vaccines: Reduces the risk of adverse reactions which can be mild like soreness to severe anaphylaxis and immune system stress. A weakened immune system is one of the factors leading to auto immune diseases and cancer, both of which are common in Berners. 
• Identifying truly at-risk pets: Ensures that vaccination targets the animals who need it most.
• Customized vaccination schedules: Adapts timing to a pet’s health, lifestyle, and environment.
• Science-based decision-making: Challenge studies have proven that antibody levels above certain thresholds prevent infection entirely.

There is an excellent correlation between a “positive” titer and protection against viral challenge with canine distemper virus (CDV); canine adenovirus (CAV-2); and canine parvovirus2 (CPV), and Rabies (RV). These are the minimum levels of antibody titer that provide immunity for distemper, adenovirus, and parvo.

CDV: SN > 1: 32
CAV-2: SN > 1: 32
CPV2: HI > 1: 80

When reading a titer level, the higher the number means the greater the protection- see side bar 1 for the titer results of the dam which shows 2560 for parvo and 256 for distemper. This means that she would be protected from distemper with a 1:80 dilution but she has a 1:256 dilution so her level is much higher. 

For already-immune pets, another dose of vaccine doesn’t make them “more” immune — it only adds antigen, adjuvant, and preservatives, which can sometimes trigger adverse effects. “Even the best vaccines can cause reactions, and when the risk has no benefit to offset it, it’s an unnecessary gamble with your pet’s health” Dr. Laurie Larson. 

Nomographs: Timing Puppy and Kitten Vaccines Perfectly

Puppies and kittens are born with a borrowed immune system, thanks to antibodies they receive from their mother’s colostrum during the first hours of life. While these maternal antibodies offer protection, they can also block vaccines from working if given too early.

The tricky part? We rarely know exactly when these antibodies fade to a low enough level for vaccines to take effect. That’s why conventional vets give young animals multiple rounds of shots — to increase the odds that one dose will “take.” As a holistic vet for a puppy without the information from a nomograph, I recommend distemper/ parvo vaccine at 9 weeks, 13 weeks, and 17 weeks then titer 2 weeks later or most people will elect to titer the following year and then Rabies at 6 months. 

A nomograph changes the game. By testing the mother’s antibody levels 2 weeks before or after birth, veterinarians or breeders can calculate when her litter will likely be ready for effective vaccination. This means:

• Fewer unnecessary shots
• Earlier confirmed immunity in some litters
• Reduced risk of the “danger window” when a pup is unprotected but still too young for vaccines to work

In a 2020 study, puppies whose vaccination schedules were based on a nomograph had significantly higher protection rates for distemper and parvovirus compared to litters without nomograph-guided timing.

The Limits of Titer Testing

• Rabies law: Rabies titers aren’t legally accepted in most areas to replace required rabies boosters but they can be used to confirm immunity and may be acceptable as proof for boarding or grooming.
• Immunity snapshot: Titers measure antibodies at one moment in time; levels can change so I recommend checking titers every 3 years. 
• Incomplete picture: Titers assess circulating humoral immunity (circulating antibodies in the blood) and don’t assess cellular immunity, another key part of disease protection. Cellular immunity focuses on eliminating pathogens within cells.  So a dog with a low antibody titer may still have cellular immunity and may still be able to fight off infection if the pet is exposed. Therefore, patients with low titers may in fact still be protected.
• One of the challenges facing the wider adoption of titer testing is skepticism among some conventional veterinarians who are not familiar with the science behind titers or the latest research on vaccine duration and immunity. Pet parents may need to have a respectful conversation with their vet and be their pet’s advocate based on knowledge they have gathered on their own. 

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Smarter Vaccination, Healthier Pets

The ultimate goal of vaccination is protection — not just “being up to date” on shots. Titer testing and nomographs offer pet parents and veterinarians a way to give the right vaccines at the right time, and only when truly needed. This approach respects the individuality of each animal and makes medical decisions based on facts and data and not tradition. 

By using these tools, we can reduce the risks of over-vaccination, improve individual animal care, and still achieve herd immunity in our communities.

Resources for Pet Owners and Vets:

• University of Wisconsin-Madison Titer Testing and nomographs: vetmed.wisc.edu/lab/cavids
• Hemopet Hemolife Diagnostics: hemopet.org/titer-testing
• Holistic vets can submit titers to Kansas state at a reduced rate thru their AHVMA (American holistic veterinary medicine association) membership vs conventional vets sending them to Idexx or Antech at a much higher cost
• Find a Holistic Veterinarian: ahvma.org or https://alumni.chiu.edu/ or https://www.ivas.org/vets/ or https://civtedu.org/directory 
• In-house titer tests like VacciCheck and TiterChek give a pos or neg response and not an actual number. Since these tests are not quantitative, they should be checked annually.  I prefer the quantitative tests from U of W, Hemopet, and KSU. 

Other key points about vaccines:

• Rabies vaccine is often given with other boosters for convenience, when this is ill advised, as Killed, inactivated vaccines like rabies make up 15% of veterinary biologicals used, but 85% of the post-vaccination reactions. Use only thimerosal (mercury) – free rabies vaccines
• The immune system mounts a faster more powerful anamnestic response when encountering the same antigen again – e.g. with viral exposures and vaccines
• The immune system capacity for memory generates immunity through vaccines, but can also trigger adverse events like autoimmune disorders and allergies/hypersensitivity
• Vaccination may not equate to immunization But, vaccinated and truly immunized animals should be fully protected from disease; Immune memory cell immunity should persist life long
• Giving boosters to immunized animals is unwise, as it introduces unnecessary antigen, adjuvant and preservatives
• AAHA 2003 – Current knowledge supports the statement that “No vaccine is always safe, no vaccine is always protective and no vaccine is always indicated”
• Heavy metal exposure from vaccines is an emerging concern for humans, pets and livestock
• The safest and most effective interval for immunization is 3-4 weeks apart. 
• Vaccinosis – Dogs and cats with immune-mediated diseases or predisposed to them are especially vulnerable to vaccinosis, since over-vaccination places additional stress on their already compromised immune systems and has been linked to autoimmune disease.  Vaccinosis in dogs refers to a state of chronic ill health resulting from adverse reactions to vaccinations, potentially compromising the immune system. While vaccines are crucial for preventing infectious diseases, over-vaccination can lead to various side effects, including injection site reactions, fever, lethargy, and allergic reactions. In some cases, vaccinosis can be linked to autoimmune diseases and chronic health issues later in life. 
• Symptoms of Vaccinosis: 
• Injection site reactions: Pain, swelling, and hair loss at the injection site. 
• Temporary effects: Fever, lethargy, and reduced appetite. 
• Allergic reactions: Ranging from mild and temporary to severe and life-threatening. 
• Autoimmune responses: Some studies suggest a link between vaccination and autoimmune diseases like autoimmune hemolytic anemia (AIHA) and immune-mediated thrombocytopenia (ITP). 
• Neurological issues: Postvaccinal polyneuropathy has been associated with certain vaccines. 
• Behavioral changes: Some dogs may exhibit anxiety or stress around the time of vaccination. 

Sidebar 1: Titer Test 101

What it is:
A blood test that measures antibody levels against specific viruses.

How it works:

1. Draw blood from your dog or cat.
2. Send to lab for quantitative or in house for “yes/no” screening.
3. Mix diluted serum with virus to see if antibodies neutralize it.
4. Report results as a number (quantitative) or positive/negative (screening).

Commonly tested viruses:

• Dogs: Canine distemper, parvovirus, adenovirus, rabies
• Cats: Feline panleukopenia, calicivirus, herpesvirus, rabies

What results mean:

• High/Positive: Likely immune → no booster needed yet
• Low/Negative: May need booster → discuss with vet

Sidebar 2: Core vs. Non-Core Vaccines

Sidebar 3: Nomograph in Action

Purpose: Predict when maternal antibodies fade enough for vaccines to work.

Step-by-step:

1. Test the dam’s titers 2 weeks before or after giving birth.
2. Lab calculates antibody half-life and estimates safe vaccine window for pups/kittens.
3. Vaccinate at optimal time for maximum effectiveness.
4. Confirm with titer test to ensure immunity took hold.

Benefit:
Higher immunity rates in puppies, fewer unnecessary shots, safer protection.

Infographic 1- Maternal Antibody Decline

Maternal antibodies fade every 9–12 days. Nomographs help pinpoint the safest, most effective time for first vaccines.

Sidebar 4: When NOT to Vaccinate

• During estrus
• Just before estrus (30 days)
• During pregnancy or lactation
• While sick, anesthetized, or on immunosuppressive drugs
• Pets with a history of serious vaccine reactions (consider titers instead)
• Geriatric animals vaccinated only with caution
• Pets with chronic diseases such as cancer or autoimmune diseases.

This article was compiled by personal knowledge as well as information from esteemed veterinarians Dr. Karen Becker, Dr. Laurie Larson from University of Wisconsin, Dr. Schultz, Dr. Jean Dodds from Hemopet.