An increase in whooping cough across New Mexico underscores once again why childhood vaccinations are so important.

Currently, New Mexico is experiencing one of its worst outbreaks of whooping cough — pertussis — with some 243 cases of the bacterial illness reported to the New Mexico Department of Health this year; 130 in Bernalillo County alone. That's compared to only 150 cases reported statewide in 2010. Unfortunately, say state health officials, the outbreak patterns seem to link the disease to places — including Santa Fe, Taos and Bernalillo counties — where more parents are seeking exemptions from vaccinations.

The whooping cough outbreak comes amid a national movement of parents who are choosing not to vaccinate their children. A recent Associated Press survey of states showed exemption rates of as high as almost 9 percent in Alaska. In rural Washington state, vaccination exemption rates can be as high as 50 percent. In eight states, more than 1 in 20 public school kindergartners do not have all their shots. Exemptions aren't as high in New Mexico, where there has been a concerted effort in recent years to improve immunization rates. One standout is White Mountain Medical Clinic in Ruidoso, which reported an immunization rate of 98 percent this year.

However, beliefs about immunizations have shifted from accepted to controversial, from life-saving to threatening, with pseudo-science affecting the opinions of parents who just want to do the best for their children. Unfortunately, a parent's attempt to do what is best can adversely affect other children. Diseases believed to be nearly eradicated — measles, whooping cough, chicken pox — are returning in clusters. Memories of the deaths and injuries from diseases such as polio, though, are fading. While New Mexico has not suffered from any deaths in this recent whooping-cough outbreak, the disease can have other severe consequences, with a cough that can last 10 weeks. Last year, in California, a whooping-cough outbreak affected more than 2,100 children, and 10 babies died.

Why don't parents want their children vaccinated? In the case of rural Washington, the reasons might be libertarian objections to government rules about vaccinations. In Santa Fe and Taos, alternative-medicine believers prefer to forgo vaccinations or take them on a different schedule. It's an unlikely alliance, the health care equivalent of the tea party and occupy movement sharing a beer.

The trouble with such opt-outs is this: For vaccinations to work, they need to be nearly as universal as possible. Outbreaks of disease that begin in a nonvaccinated cluster of children can affect kids who received their shots because inoculations aren't 100 percent effective every time. A pregnant woman, for example, faces severe complications if exposed to measles and other infectious diseases. Infants too young to be vaccinated are particularly at risk during an outbreak. Even vaccinated children with respiratory diseases have to take preventive antibiotics — many with severe side effects — if exposed to whooping cough.

Vaccines can lose effectiveness, so adults and older teenagers who become ill, also face dangerous outcomes. Deciding not to vaccinate is an individual choice that affects the group as a whole. Because of near-universal vaccinations, childhood diseases and the misery they left behind have become a fading memory. By choosing to vaccinate their children, parents will help keep such horrors in the past — where they belong.