Vaccines

scroll down

Vaccines Objectives

Describe the status of vaccines used to prevent AIDS, malaria, TB, and measles.
Explain why people have to keep getting flu vaccines year after year.
List issues associated with developing an effective vaccine against SARS-CoV-2.

In controlling infectious diseases, an effective vaccine is the “gold standard” for reducing significant infections.

An important aspect of vaccination that is often overlooked is that this is not necessarily a process for a particular individual; this is for society. Some people can not be immunized because they are too young, too ill, or have a compromised immune system. If everyone else is vaccinated, this provides “herd immunity” that protects the most vulnerable people from being exposed to the pathogen.

There can be significant challenges in developing effective vaccines. An effective vaccine has few side effects, causes the body to produce sufficient and lasting memory cells, and is cost effective.

One of the most researched vaccines is against strains of influenza. The flu virus mutates at a rapid rate and has the potential to cause pandemics as occurred in 1918 with the “Spanish flu” that killed tens of millions of people in a year’s time.

This video provides information about influenza infections.

Altered viral antigens can result in memory cells no longer recognizing the pathogen when it enters the body.

Covid Vaccine

Q. What questions remain about the new covid-19 vaccines?

A. The vaccines against covid-19 have been shown to reduce the risk for severe illness and death from SARS-CoV-2. Questions remain about how frequently boosters will be needed, and whether they will be effective against emerging viral variants. It takes time to study vaccine efficacy. A vaccine was not developed for SARS-CoV-1 since a combination of luck and strict quarantining stopped the spread. As a result, we do not know how vaccines against SARS will function over extended periods of time.

If you would like to learn more about the original SARs outbreak, there are archived CDC web pages available.

Q. Will quarantining be over for good, now that we have a vaccine and boosters?

A. Herd immunity is the idea that enough people are not carrying an active pathogen so those who are not vaccinated like immunocompromised or the very young are not exposed to the pathogen. The goal is to reach a significant number of people, 85 to 90% who have memory cells either from being directly infected, or in a less risky manner, from a vaccine. They are less likely to carry enough viral load to infect other people. An effective vaccine would have to be administered widely to people who have not been exposed to the virus, and that is taking time. Repeated infections, even in the vaccinated is indicating short “memory” of the virus. Even if a vaccinated person does not get severely ill, they could pass the virus to someone who is unvaccinated and at risk for severe illness. Additionally new variants may lead to future quarantines.

This is the end of the Eliminating infectious Diseases guide. Material from this guide and corresponding lecture, along with the next Current Pandemics guide, are assessed on the weekly quiz.

Check your knowledge. Can you:

describe the status of vaccines used to prevent AIDS, malaria, TB, and measles?
explain why people have to keep getting flu vaccines year after year?
list issues associated with developing an effective vaccine against SARS-CoV-2?