(CNN) -- Pregnant women should receive a whooping cough vaccine in the second half of each pregnancy, according to this year's recommended vaccine schedule for children and adolescents.
In addition, the new schedule - published Monday by the American Academy of Pediatrics (AAP), along with the Centers for Disease Control and Prevention and the American Academy of Family Physicians -- consolidates the schedules into one comprehensive list, covering children from birth through age 18.
That's a change from previous years, when the schedule was separated into two different lists, for ages 0 to 6 and 7 to 18. The new schedule will also include an additional column that highlights which vaccines 4-to-6-year-olds and adolescents need.
The schedule, which is published every February, tells parents and doctors when is the correct time to vaccinate children against the 16 infectious diseases for which vaccines are available, said Dr. Cody Meissner, head of the pediatric infectious disease division at Tufts University Medical Center and a consultant for the AAP's Committee on Infectious Diseases. The schedule is updated yearly to reflect any changes based on new research or developments.
It is now recommended that pregnant adolescents women receive a whooping cough (Tdap) shot in the final half of pregnancy, every time they are pregnant.
"After mom gets the booster dose during pregnancy number one, the immunity peaks and then wanes pretty quickly," explains Meissner. The rational behind this recommendation is to vaccinate women near their time of delivery to boost immunity, which then passes through the placenta and get into the baby - so the baby will have its mother's immunity until it can develop its own.
Whooping cough cases have risen to a 50-year high, the CDC said last year.
"There will be about 20 (whooping cough) deaths for 2013," says Meissner. Ninety percent of pertussis deaths occur in the first three months of life, he adds. That's because children in the first three months are too young to acquire immunity from their first (inoculation), which doesn't even occur until they are two months old. So having mom confer immunity to the newborn and having others around the babies, including grandparents, inoculated can protect the unvaccinated child.
Despite assurances that these vaccines are safe, more parents are choosing to delay getting their children vaccinated or not vaccinating them at all. Just last week, a study in the Journal of the American Medical Association (JAMA) found "undervaccination appears to be an increasing trend."
And two weeks ago, a report from the Institute of Medicine not only found no evidence of major safety concerns when following the recommended vaccine schedules, it also "confirmed that following the schedule strongly reduces the risk of disease."
Meissner says it's "such a mistake for people not to vaccinate according to the current schedule." He adds that "a vaccine is not added to the vaccine schedule by FDA, CDC, AAP unless we are absolutely convinced of the benefit of that vaccine and the safety of the vaccine."
Still, some have suggested there are alternate ways to vaccinate children by either spacing out the vaccines or even dropping some.
"There is no "alternate" vaccine schedule," says Dr. Paul Offit, chief of the infectious diseases division at Children's Hospital of Philadelphia, co-inventor of a rotovirus vaccine and author of "Deadly Choices: How the Anti-Vaccine Movement Threatens Us All." He says about 13% of parents are choosing not to vaccine or delay vaccinating their children and "that's a dangerous thing to do" because the vaccine-preventable diseases can kill.
Dr. William Schaffner, chairman of the Department of Preventive Medicine at Vanderbilt University Medical Center, says "there isn't any doubt, there are increasing exceptions to the ACIP/AAP immunization schedule."
Childhood vaccinations are being ignored for a variety of reasons, he says. "There are those who are vaccine skeptics or parents don't get around to it; parents are forgetful, or children are not able to get vaccine for health reasons and are listed as not receiving vaccine."
This opens the door for the occasional importation of disease, like measles - which is still very much present in other parts of the world, he says. "I find this disquieting because I think there will be more clusters of more spread of forgotten disease."
The 2013 vaccine schedule calls for vaccinating against 16 diseases: Diphtheria, tetanus, pertussis (whooping cough), Haemophilus influenzae type b (can cause meningitis, arthritis, pneumonia), Hepatitis A, Hepatitis B, Human papillomavirus (HPV), Influenza (flu), measles, mumps, rubella (German measles), meningococcal (can cause meningitis, sepsis), pneumococcal (incl. ear infections, pneumonia, meningitis), Poliomyelitis (polio), rotavirus and varicella (chickenpox).
™ & © 2013 Cable News Network, Inc., a Time Warner Company. All rights reserved.