In The Know: Less Commonly Discussed Vaccines

We always hear about getting the flu shot during flu season or the COVID-19 vaccine during the pandemic. But what about all of the other vaccines that are out there? There are several types of less commonly talked about vaccines that are designed to teach your immune system how to fight off certain kinds of germs, along with the serious diseases they cause.

How do scientists think when creating these vaccines?

 When scientists create vaccines they consider a lot of different factors, such as how the immune system will respond to the germs, who needs to get vaccinated against these germs, and the technology/approach used to create the vaccine. ¹

Different Types of Vaccines

There are several different types of vaccines, the most common being:

Inactivated Vaccines

Inactivated vaccines are created by using the killed version of the germ that causes a sickness. These vaccines don’t provide as much protection as other vaccines, which is why it is recommended to get several doses over time to keep immunity against these diseases.

Some examples of inactivated vaccines are:

• Hepatitis A

• Flu (shot only)

• Polio (shot only)

• Rabies

Live-attenuated vaccines

Live vaccines use a weakened form of the germ that causes a disease to protect against it. Since these vaccines are similar to the disease that they help to prevent, they create a strong and lasting protection. Even one to two simple doses give you a lifetime of protection.

However, these vaccines also have some limitations. For example, they need to be kept cold, which means they don’t travel well. This means that some of these vaccines can’t be used in countries that have limited access to refrigerators. Additionally, because they contain a small amount of the weakened live virus, people with weakened immune systems, long term health problems, or people who have had an organ transplant should talk to their health care provider before receiving them.

Live vaccines are used to protect against:

• Measles, mumps, rubella (MMR is the combined vaccine name)

• Rotavirus

• Smallpox

• Chickenpox

• Yellow fever

Messenger RN vaccines (mRNA)

Many researchers have been studying and working with mRNA vaccines for decades, with this technology being used to make some of the COVID-19 vaccines. mRNA vaccines make proteins to trigger an immune response and have several benefits compared to other vaccines, such as shorter manufacturing times and no risk of causing disease in the person getting vaccinated, since they don’t contain a live virus.

mRNA vaccines are used to protect against:

• COVID-19

Subunit, recombinant, polysaccharide, and conjugate vaccines

Subunit, recombinant, polysaccharide, and conjugate vaccines all use specific pieces of a germ, such as the protein, sugar, or the casing around a germ. Since these vaccines use specific parts of the germ, they give a strong response that’s targeted to key parts of the germ. This means that almost anyone can get these vaccines.

One limitation of these vaccines is that you may need booster shots to continue getting protection against diseases.

These vaccines help to protect against:

• Hib (Haemophilus influenzae type b) disease

• Hepatitis B

• HPV (Human papillomavirus)

• Whooping cough (part of the DTaP combined vaccine)

• Pneumococcal disease

• Meningococcal disease

• Shingles

Toxoid vaccines

Toxoid vaccines use a harmful product made by the germ that causes the disease. They help create immunity to parts of the germ that cause disease instead of the germ itself, which means the response is targeted to the toxin instead of the whole germ. You may end up needing booster shots to get ongoing protection against these diseases.

These vaccines help to protect against:

• Diphtheria

• Tetanus

Viral vector vaccines

Scientists have studied viral vector vaccines for decades, with some of these vaccines being recently used for the Ebola outbreak and being studied for use against other infectious diseases such as Zika, flu, and HIV. This technology was also used to make COVID-19 vaccines.

These vaccines use a modified version of a different virus as a vector to deliver protection. A few different viruses that have been used as vectors are influenza, vesicular stomatitis virus (VSV), measles, and adenovirus. Adenovirus, which causes the common cold, is one of the vectors used in COVID-19 vaccines that are being studied in clinical trials.

These vaccines help to protect against:

• COVID-19

When to get these vaccines?

Many of these vaccines are ones that you likely already had administered when you were a child, with the ages ranging from 2 months to 12 months for certain vaccinations. But there are a select few vaccines that you need if you’re traveling to certain parts of the world or are exposed to certain diseases. ²

Japanese Encephalitis (JE)

This disease is common in Asia and can cause inflammation of the brain, which can be deadly. ³ JE isn’t found in the United States and thanks to this vaccine, it is rare for travelers to get this disease. This vaccine is recommended for people living or traveling to parts of Asia where JE is a risk, along with the following:

• People who plan to spend 1 month or more in a place where JE is common.

• People who spend any time in a place with JE and will be outside in a rural area or staying somewhere without air conditioning, mosquito nets, or window screens.

• People who plan to travel to an area with a JE outbreak.

This vaccine is given in 2 doses, with these doses given one month apart, and the second dose needing to be at least 1 week before your trip. If you want more information on this vaccine, you can always ask your doctor or look online for more information. ⁴

Typhoid Fever

Typhoid fever ⁵ is rare in the United States but is still common in some countries. Around 5,700 people get sick with typhoid in the US every year, usually after traveling to other countries. There are two ways that you can get the typhoid vaccine, the shot or the pill.

This vaccine is recommended for people at high risk of coming in contact with typhoid. You may need to get the vaccine if you:

• Are in close contact with someone who has typhoid

• Work in a lab studying the disease

• Are traveling to a country where typhoid is common

If you get the typhoid shot, you will need 1 dose at least 2 weeks before traveling and then get a booster every 2 years. Then if you get the oral typhoid vaccine you will need 4 doses every other day for a week, with the last dose taken at least a week before travel, and a booster every 5 years. You can always talk to your doctor to find out if this vaccine is recommended for you or check out the CDC’s travel website ⁶ for more information.

Yellow Fever

Yellow fever is most common in parts of Africa and South America but is not found in the United States. ⁷ This vaccine is recommended only for people who are living or traveling to places where yellow fever is a risk. This vaccine can be given in one dose to travelers who are 9 months and older, with a booster needed every 10 years. Some countries also require proof that you’ve been vaccinated against yellow fever and ask for an International Certificate of Vaccination or Prophylaxis. ⁸

Cholera

Cholera is rare in the United States but is still common in other countries, with more than 95,00 around the world that die from cholera every year. ⁹ The cholera vaccine can help to lower your risk while traveling. This vaccine is an oral vaccine, which is a pill that you take. Most people don’t need to get the cholera vaccine, but doctors do recommend it to people ages 18 through 64 years, who are traveling to an area where cholera is common.

Rabies

Rabies ¹⁰ is a rare disease in the United States but when it occurs it’s almost always deadly. The rabies vaccine helps to prevent this disease from spreading and is given to people who are at a higher risk of coming in contact with rabies, such as veterinarians or people bitten by an animal that could have rabies.  If you’re bitten by an animal that could have rabies you should contact your doctor right away. ¹¹

Vaccination is the most important thing we can do to protect ourselves and our children against the diseases that are around us. Vaccines help to prevent millions of deaths worldwide every year. ¹² So, make sure to stay up to date on all of your vaccinations, get your information from trusted professionals such as licensed pharmacists and doctors, and spread the word about the power of vaccines.

Sources:

1. https://www.hhs.gov/immunization/basics/types/index.html 

2. https://www.hhs.gov/immunization/diseases/index.html 

3. https://www.hhs.gov/immunization/diseases/je/index.html 

4. https://www.immunize.org/vaccines/vis/japanese-encephalitis/ 

5. https://www.hhs.gov/immunization/diseases/typhoid-fever/index.html 

6. https://wwwnc.cdc.gov/travel/ 

7. https://www.hhs.gov/immunization/diseases/yellow-fever/index.html 

8. https://wwwnc.cdc.gov/travel/yellowbook/2024/preparing/yellow-fever-vaccine-malaria-prevention-by-country 

9. https://www.hhs.gov/immunization/diseases/cholera/index.html

10. https://www.hhs.gov/immunization/diseases/rabies/index.html 

11. https://www.cdc.gov/rabies/when-to-seek-care/?CDC_AAref_Val=https://www.cdc.gov/rabies/exposure/index.html 

12. https://www.nhs.uk/vaccinations/why-vaccination-is-important-and-the-safest-way-to-protect-yourself/