Shanghai disease control authorities have taken emergency measures to vaccinate 400 residents of the Changqiao residential community in Xuhui district after a visitor from Anhui Province was diagnosed with measles, local media reported Tuesday.

The case highlights the city's fragmented system for vaccination records as local health authorities demand almost all nearby residents to get vaccinated whenever a measles case appears.

"Everyone more than six months old needs to be vaccinated," a member of the Changqiao neighborhood committee told the Global Times.

The visitor was a woman in her 20s from Anhui Province who came to the community to visit a friend while in Shanghai, the committee member said.

Seven doctors were dispatched to administer free vaccinations to residents in seven of the community's buildings on the same day the Anhui woman was diagnosed, according to a report in the newspaper Youth Daily. It took three and a half hours to vaccinate the residents.

"It is a regular measure that we take whenever a measles case is reported," a staff member surnamed Ding from the Changqiao Community Health Service Center told the Global Times.

The emergency measure, however, sometimes leads people who have already been vaccinated to receive an unnecessary dose, an insider from the Shanghai Municipal Center for Disease Control and Prevention said.

"It was not until recently that Shanghai built a digital system to track vaccinations," he told the Global Times. "Many people above 20 years old have already lost their record cards. People do not remember whether they have been vaccinated for a certain kind of disease."

According to a 2006 plan by the Shanghai Health Bureau, the city aims to push down the annual measles incidence rate to less than one for every 1 million residents by the end of this year.

However, the insider said that the city may be going about measles eradication in the wrong way. "While school-age children receive repeated vaccinations, authorities do not pay enough attention to migrants, which are the primary problem group in keeping down the incidence rate," he said.

The measles incidence rate jumped from five per 1 million residents in the 1990s to 166 per 1 million residents in 2005 because of the rise in the migrant population, according to the plan.

"The measure should leave out local school-age children as almost all of them have been vaccinated for measles. Although the extra dose is not harmful, it is a waste of money and effort, and does not help control the disease," the insider said.