Most of us have had “that nagging cough” at least once in our lives. But recent headlines remind us that pertussis — or “whooping cough” — continues to increase nationally, leading to the most cases in more than 50 years.

I saw a patient recently who complained of a cough persisting for more than six weeks. It wasn’t getting worse, just hanging in there. While an exam proved it was not the dreaded pertussis, more likely allergies from all this dry, dusty air we’re having, it’s sometimes hard to tell.

Peak months for the infection range from June to September. Children and adults can get it, but it can be particularly life-threatening to infants. Here’s what you need to know to ward off the risk.

Pertussis occurs in three stages. Older children, adolescents and adults may not go through all three and may just have a persistent cough that triggers headaches.

• The first stage looks like a common cold with nasal congestion, sneezing, a low-grade fever and the like. It lasts from one to two weeks. You won’t feel that sick. However, during this stage it’s most contagious.
• In the second stage, the cough can get severe. In young children, the intense coughing can last for minutes and may lead to vomiting. Some little ones will gasp for air between coughs, but the airway is narrowed, making the cough sound more like a “whoop.” Older children and adults have wider airways, so we don’t whoop as intensely. See the video below for an example.
• The third stage leads to a more chronic, less severe cough. This stage can last for weeks, which is why some people refer to pertussis as the “100-day cough.”

Antibiotics are effective in stopping the infection’s spread, but if delayed until the second stage, when the cough is more severe, they won’t shorten the course or lessen the cough.

The best protection is vaccination. Since the 1940s, many Americans have received a series of vaccines throughout their lives: three shots as a baby, a booster as a toddler and another when starting kindergarten. Because the vaccine begins to wane after three to five years, adults are often not protected. That’s why most clinicians now recommend the adult pertussis booster, which is often combined with one for diphtheria and one for tetanus, protecting us from two more serious diseases.

The challenge is that infants can’t have the vaccine until two months of age, yet the risk of hospitalization and death from pertussis is highest during this time. The key is vaccinating adults so that infants are surrounded by people immunized against pertussis. Researchers call it “cocooning” — the idea of surrounding our babies with people who are protected, especially sheltering those under 2 months old.

So get the whole family together for this one, including daycare and health care providers. Have you had a pertussis vaccine lately?