All of us have a fear of the unknown and all of us know that there is nothing more certain than death and taxes. Mix into all this fear is the role that viruses play in morbidity (sickness) and mortality (death). Viruses are particularly scary because they are so tiny up to 2000 times smaller than a grain of sand and can be so deadly. It is confusing that we have hundreds of viruses living with us every day and they don’t seem to be deadly.
All viruses carry a small piece of genetic information (DNA or RNA) inside of a protective coating (capsid). It can be thought of as an envelope carrying instructions. Our body cells are like an entire factory carrying both the instructions and the equipment to carry out the instructions, making proteins and making more cells. Viruses have to break into our cells and use their machinery to make copies of the instructions or to replicate.
Prominent in today’s news is Hepatitis B. There are 5 viruses that cause an inflammation of the liver, hepatitis A, B, C, D, and E. A, B and C are the most common and are associated with significant illness and cancer. Hepatitis B is usually a short time illness but it can become chronic liver disease or liver cancer.
One of the problems with Hepatitis B is that people do not know they are infected and can spread the disease. It is spread through blood, semen and other body fluids. People can be infected at birth, by sharing razors or tooth brushes, by contact with blood or open sores, sex with infected partner or by contaminated needles.
The good news is that most people who get vaccinated against hepatitis B are immune for life. The vaccine is 95% effective at preventing this disease in children and adults. Babies have incredible immune systems and are given the first hepatitis B vaccine within 24 hours of birth. This provides a safety net for babies whose family members may not know they are infected. There are two more vaccine doses at 1-2 months and then between 6-18 months. The vaccine has been tested extensively for safety and it works. Rates of acute hepatitis B are steadily declining.
If babies get infected with hepatitis B, they have a 90% chance of developing chronic hepatitis B. Sadly, 25% of the babies who get chronic hepatitis B die.
There at least 7 groups of viruses that cause cancer by different mechanisms. There is now a vaccine preventing human papillomaviruses (HPV) also.
People under increased risk from certain types of viruses are those under 5 or over 65, have certain health conditions like asthma, diabetes, COPD, have a weakened immune system (cancer, immunosuppressive medications) or are pregnant.
Hopefully knowledge about viruses and their vaccines will help making good decisions for preventing disease to insure a long, healthy life.
The American Academy of Pediatrics (aap.org) remains a good resource for information on vaccines and health guidance for families.
American Academy of Pediatrics (aap.org) a trusted source for vaccines.
by Sally Robinson, MD Clinical Professor
Keeping Kids Healthy
Published 9/2025