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Published on April 24, 2019

How do Vaccines Work?: Q&A with Pharmacist Alicia Rogers

Measles virus

How do vaccines work?

The ultimate goal of a vaccine is to protect the patient (adult, mother, father, baby, etc.) from very dangerous and even deadly diseases. This is done by exposure to a small amount of the virus. Vaccines work with our body's natural defense system to produce an immune response. This response can ramp up the production of antibodies which can cause minor reactions such as a fever, headache, tiredness. After a couple weeks, your body remembers that initial immune response to the vaccine so that it can fight the disease in the future.

Why are there so many vaccines?

Think of all the disease states that we have or had in the past (Diabetes, Cancer, Shingles, Hepatitis A, Hepatitis B, Flu, Polio....). The list can get very detailed very fast. Now, imagine if there was a vaccine series to prevent or lessen the symptoms of all of these disease states. Yes, this is far-fetched. We can't treat all disease states with one super vaccine. Just like with any medical specialty, we treat each individual disease state while taking care of the whole patient.

Is it better for a child to acquire a childhood disease, like chickenpox, or be vaccinated? Why?

I had chickenpox as a child. In fact, my entire family of 8 kids all had it at the same time. Some of us had it significantly worse than others with oral lesions. We didn't leave the house for days, as we were all highly contagious until 24 hours after no new lesions appeared. "Chickenpox Parties" are something that exist, but why take the chance?

Chickenpox can lead to serious complications including death, and there's no way to predict individual response to the virus. Also, we must consider those that may be unintentionally harmed by our exposure. Vaccination is the best protection and is a safe way to avoid undue illness, family burden, and time away from work, school, and other activities.

Do vaccines cause autism, multiple sclerosis or other illnesses?

Bottom line - there is no link between vaccines and autism. Vaccine ingredients do not cause autism. A physician falsified information for a "study," which had huge ramifications on societal beliefs around vaccination and why we do it. This physician has been completely discredited and labeled a fraud, but people don't forget. Sadly, due to this study several pockets of measles outbreaks are occurring in our country, especially in NYC.

Yes, vaccines have side effects just like medications & some of these side effects are more severe than others. For example, Guillain-Barre syndrome is a rare side effect that may develop weeks after vaccination. Thimersoal is a type of preservative used in vaccines to prevent contamination. Several studies have recently been conducted to rule out a link between thimersol and autism as well as other neurologic disorders. Upon review of a vaccine package insert today, you will see that thimersoal is listed as "trace amounts." There was never any proof that this preservative was harmful, but manufacturers figured​ out different production strategies.

Just with anything in life, becoming fully educated around the matter whether it's vaccination, surgery, or starting new medications is always best. What are the risks vs. benefits? There are great sites such as the CDC ( and IAC ( These sites help answer questions and debunk myths in order to provide parents and patients with helpful links and tools to make better educated decisions.

Do vaccines contain aborted fetal tissue and/or unsafe toxins?

There is a lot of confusion and misleading information on this topic with 2 false statements that ongoing abortions are needed for manufacturing and that vaccines are contaminated with fetal tissue. These are not true statements. In the 1960s, two human cell lines were developed from aborted fetuses and these original cell lines survived. Yes, these cell lines provided the initial cell culture for growing vaccines, but no fetal tissue has been added since their origination. Some vaccines today, varicella and rubella, do involve growing the virus in human cell culture, which creates a lot of religious morality questions and concerns.

In 2003, a Catholic bishop and congregation produced a careful examination and study to conclude that the parents have no general obligation to refuse vaccination due to these issues cited above. A documented paper was published on the study which examines each vaccine in question in great detail and the moral dilemma that arises from a religious perspective. If this is your personal hurdle for choosing not to vaccinate, then please read the following "Moral Reflections on Vaccines Prepared From Cells Derived from Aborted Human Foetuses." (

Can getting a vaccine give me the disease it was supposed to prevent?

Most vaccines that are manufactured today are not live vaccines; therefore, you cannot get the disease from the vaccine. The side effects that you notice from the vaccine, such as the flu vaccine, are simply mild symptoms from the vaccine indicating that your body is creating an immune response. Your body's immune response may take about 2 weeks to build up, so if you are around flu activity in that time there is a chance that you may still get the virus.

The MMR (measles, mumps, & rubella) vaccine contains a weakened, but live, virus that may cause a rash in about 5% of patients, which may stress parents. It's imperative that your physician, pharmacist, and/or nurse review the Vaccine Information Sheet (VIS) for side effects to take note of prior to any vaccine. Most vaccines do have mild side effects, such as fever, nausea, headache, injection site reactions, etc., anything more serious should be reported to your healthcare provider after administration. Please note these side effects are temporary, lasting 3-5 days whereas complications from the disease itself could be life-long.

Can babies’ immune system handle so many vaccines?

Vaccine recommendations for children and adults are reviewed annually and updated when necessary after extensive, large clinical trials. The primary goal is early protection. The greater length of time our children go unvaccinated, the more susceptible they are to contract these diseases. No scientific evidence exists to delay or separate the vaccination schedule. More trips to the pediatrician office increase the chance for delayed vaccination resulting in vulnerability. Don't delay vaccinations.

Aren’t better hygiene and sanitation actually responsible for decreased infections as opposed to vaccines?

Hygiene and sanitation help to significantly reduce transmission of diseases and viruses, such as the flu-virus. However, several of these disease states are transmitted through air particles such as coughing and sneezing. Furthermore, if better hygiene were to credit, then the chickenpox rate would have dropped significantly before the introduction of the vaccine. Many of us can still remember having chickenpox as a child, as this disease state didn't significantly decline until about 2004 with the vaccine introduction in 1995. Again, proper hygiene and vaccination work together to combat these diseases.

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About the Author

How do vaccines work?Alicia Rogers, Pharm D., is a pharmacist with Moses Cone Outpatient Pharmacy