All pregnant women should be vaccinated against pertussis, also known as whooping cough, a U.S. government panel advises.

Pertussis is a highly contagious bacterial disease that attacks the respiratory system. Pregnant women should receive the in their last trimester. Getting vaccinated during pregnancy means a mother can pass immunity to whooping cough to her baby and the shot would protect newborns from it.

So far, more than 32,000 cases have been reported and 16 people have died, most of them infants from whooping cough, according to the U.S. Centers for Disease Control and Prevention.

Of the infants who get pertussis, 30 to 40 percent get it from their mothers and more than half need to be hospitalized. According to the CDC, of those babies hospitalized, one in five gets pneumonia and one in 100 dies.

Since infants can only start getting the pertussis vaccine at two months of age, mothers need to have immunity passed to them by their mothers.

Dr. Marc Siegel, an associate professor of medicine at NYU Langone Medical Center in New York City, said the vaccine is safe during pregnancy. He also said that immunity is also passed to the infant through breast milk, a process called passive immunity.