Times Colonist

Vaccines boost immune system

- DR. KEITH ROACH Your Good Health

Dear Dr. Roach: I will never willingly get a vaccine for anything. I have been sick only once in my life, and it was from a vaccinatio­n that I received in the seventh grade. I am now 80. Besides my bad experience, I do not get vaccinatio­ns because I do not know what they are. Also, I do not know the difference between a virus, a germ and bacteria nor how they make a person sick.

How do these things interface with the cells that make up our bodies? Many of us cannot accept the advice to “take this, because it will prevent whatever.” If I had the medical details, I might reconsider vaccinatio­n.

Anon.

Making a medical decision should ideally be based on the best, most up-to-date informatio­n. For more than 65 years, you have been choosing against one of the most important medical interventi­ons we have, based on a single bad experience. I assure you that vaccine technology is much, much better now than it was in the 1950s.

Vaccines get your body’s immune system prepared to fight a specific infection. Infections are caused by germs, but “germs” is an imprecise term that includes microscopi­c invaders, including bacteria, viruses, fungi, protozoa and other parasites. However, all commercial­ly available vaccines at present work against bacteria or viruses.

Bacteria are microscopi­c organisms that live virtually everywhere: Only a tiny fraction cause human disease. Viruses are structures of protein and nucleic acids that use the host cells to reproduce. Viruses take over the genetic informatio­n of a cell and force it to replicate viruses instead of performing the normal job of a cell.

Vaccines can be made to combat bacteria (such as pneumococc­us, a bacteria species that is the leading cause of pneumonia) and viruses (such as measles, the most infectious disease known). A vaccine might use either attenuated (weakened) strains of the bacteria or virus, or purified structures of the bacteria or virus. By being primed against the invader, the body is ready to respond in the case of actual exposure to infection. Both types can provide long-lasting protection from infection.

Although most vaccines are for infections that, if survived, the body has immunity to, some vaccines provide immunity to an infection that even survivors do not develop immunity to. One example is tetanus.

Vaccines teach the immune system how to make antibodies to a particular infection, and might also stimulate the cellular immune system. The way this works is complicate­d, and physicians spend months learning how the immune system works and how vaccines interact with the immune system. By contrast, vaccine scientists spend years or decades learning in great detail how to make safe and effective vaccines.

At the time I write this, I know of many different teams trying heroically to develop a safe and effective vaccine against coronaviru­s. A vaccine could prevent millions of deaths.

As a provider on the front line of taking care of these patients, I cannot express how much I look forward to a vaccine. As a person in your 80s, you should too.

Dr. Roach regrets that he is unable to answer individual letters, but will incorporat­e them in the column whenever possible. Readers can email questions to ToYourGood Health@med.cornell.edu.

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