Feature Article: Did You Know that Germs Gang Up on Us to Cause Disease?

Viruses and bacteria sometimes adopt a “kick them while they’re down” approach, leveraging the weakened state of a person’s body to cause further infection. The pathogens that cause the second infection are often referred to as “opportunistic.”

Some examples of opportunistic pathogens include:  

• Group A streptococcus (GAS), more commonly known as “flesh-eating bacteria,” can infect sores caused by chickenpox infection.
• Tuberculosis (TB) infections are one of the leading causes of death among people living with human immunodeficiency virus (HIV) because the bacteria that causes TB, Mycobacterium tuberculosis, invades the lungs of infected individuals.
• Pneumococcal bacteria often infect the lungs after they have been compromised by a viral infection such as influenza.

Let’s face it, when you are lying in bed with “the flu,” your first thought isn’t that you could get sick with something else. However, the reality is that when influenza virus causes an infection, it often opens the door for a pneumococcal infection to follow. This is why older adults are particularly at risk of hospitalization or death following infection with influenza. While some will be hospitalized or die from pneumonia caused by influenza, most will have complications due to pneumococcal infection. If you or someone you know has ever had the flu, seemed to be getting better and then ended up even more ill a few days later, you have witnessed what can happen when pneumococcus infection follows infection with influenza.

Fortunately, influenza and pneumococcal vaccines are available to protect older adults from this one-two punch. Two versions of the pneumococcal vaccine are available, and both are typically recommended for adults 65 years and older:

• The pneumococcal polysaccharide vaccine, often referred to as PPSV23, protects against 23 different types of pneumococcus. This version is made from the sugar coating of the pneumococcal bacteria.
• The pneumococcal conjugate vaccine, known as PCV13, protects against 13 types and has a “helper protein” attached to the sugar coating.

Both vaccines have different strengths. The additional protein attached to the sugar coating of the conjugate vaccine generates stronger immune responses, but the polysaccharide version offers protection against more types of pneumococcal bacteria.

Some adults are considered high risk and are recommended to get pneumococcal vaccine before they are 65 years old. These include:

• People with chronic conditions of the lungs, heart or liver, diabetes, cancer or HIV
• Those without a functioning spleen
• Those who smoke or suffer from alcoholism
• Those who are immune compromised by disease or treatment for disease

Because of the differences between the two vaccines and individual patient profiles, it’s best to talk with your doctor or healthcare provider to figure out whether you need either or both pneumococcal vaccines.

All infants should receive the PCV13 vaccine in four doses at 2, 4, 6 and between 12 and 15 months of age.

The VEC recently released a pneumococcus question-and-answer sheet (English│Spanish), with more information about the disease, its complications, and the vaccines.

Additional resources

• A Look at Each Vaccine: Pneumococcal
• A Look at Each Vaccine: Influenza
• Influenza: What You Should Know – English│Spanish