Bernacki and his team at Baltimore's largest health employer say that getting as many as possible of its health care workers vaccinated is critical to shielding patients from possible infection during hospital stays. Hospital patients are often elderly or already have weakened immune systems, making them vulnerable to flu and its complications, including death. Some 36,000 Americans die annually from seasonal influenza, leading to more than 3.1 million patient days spent in hospital and over 34 million outpatient visits.

Since 2006, the U.S. Centers for Disease Control and Prevention has recommended vaccination for all health care workers, but most nationwide still do not comply. Previous hospital surveys have shown that barely a quarter of all hospital workers get vaccinated, with somewhat better results, 42 percent, for those providing direct patient care.

To track vaccination rates at Johns Hopkins, Bernacki's team combined information from employee health records kept at the hospital and cross-checked them with results obtained from questionnaires and telephone interviews from a random sampling of hospital and university employees who work at the medical campus.

A random sampling, some 10 percent of all employees, yielded 1,084 employee names, of which 650 were already recorded in hospital databases as either having been vaccinated on site or elsewhere, or having declined the flu vaccination. The remaining 434 were followed up with by mail and phone surveys to find who got vaccinated and where, and who did not. Results showed that 132 had undergone vaccination elsewhere. Only 18 people on the call list could not be reached, a number so low that it did not skew the researcher's results.

According to the study's lead investigator, biostatician and epidemiologist Xuguang (Grant) Tao, M.D., Ph.D., the one-in-10 sampling method, combined with the follow-up survey offered a practical and effective means of accurately tracking who was and was not vaccinated on the medical campus.

"Hospitals have struggled with how to monitor compliance with the CDC's recommendation, and now we think we have a reliable tracking tool that any medical center can readily use," says Tao.

Bernacki says patients should be comfortable going to any hospital knowing that they are at the lowest possible risk of catching the flu from an infected health care worker. "Now, we have the means of telling them exactly what level of protection is being offered. Having this information publicly available can only lead to higher compliance rates and a win-win for both patients and staff."

Source: Johns Hopkins Medical Institutions