ACIP Revises Language for Tdap Vaccination of Healthcare Workers

From Medscape Medical News

Emma Hitt, PhD

February 23, 2011 — Revised language on the use of tetanus, diphtheria, and pertussis (Tdap) vaccination in healthcare personnel was voted on and approved by the Centers for Disease Control and Prevention's (CDC's) Advisory Committee in Immunization Practices (ACIP) yesterday.

The wording states that healthcare personnel, regardless of age, should receive a single dose of Tdap as soon as feasible if they have not previously received Tdap, and regardless of time since their last dose of tetanus and diphtheria toxoids (Td) vaccine.

In addition, after the receipt of Tdap, healthcare personnel should receive routine booster immunization against tetanus and diphtheria, according to previously published guidelines. Hospitals and ambulatory care facilities should provide Tdap for healthcare personnel and use approaches that maximize vaccination rates, such as providing Tdap at no charge.

In 2005, ACIP voted to recommend routine use of a single dose of Tdap for adults aged 19 to 64 years to replace the next booster dose Td vaccine. ACIP also recommended Tdap for adults who have close contact with infants younger than 12 months.

At the last meeting, in October 2010, ACIP recommended a booster vaccination with Tdap vaccine in people between aged 11 and 64 years and in those older than 65 years if they come in close contact with infants.

Today, proposed modified language on the use of Tdap in healthcare personnel was voted on by 15 members, with 14 votes in favor that the new language should be adopted and 1 abstention.

Antimicrobial Prophylaxis in Healthcare Personnel

The committee also voted on whether the use of postexposure antimicrobial prophylaxis in healthcare personnel should be expressly stated in the guidelines.

Jennifer L. Liang, DVM, from the ACIP Pertussis Working Group, described findings from a study conducted at Vanderbilt University, Nashville, Tennessee, supporting the idea that Tdap-vaccinated healthcare personnel should receive postexposure prophylaxis.

The study included 116 exposures that occurred among 94 healthcare personnel and found that pertussis infection occurred in 10% of exposed healthcare personnel who did not receive postexposure prophylaxis, whereas it occurred in 2% of exposed healthcare personnel who did receive postexposure prophylaxis.

"There may be a benefit for postexposure prophylaxis in vaccinated healthcare personnel," said Dr. Liang. "The low risk of infection in both groups suggests that both strategies may be acceptable," she added.

The new ACIP guidelines state that Tdap vaccination may not preclude the need for postexposure antimicrobial prophylaxis, which is recommended for all healthcare personnel who have unprotected exposure to pertussis and are likely to be exposed to a patient at risk for severe pertussis; for example, hospitalized neonates and pregnant women.

According to the new guidelines, healthcare personnel should receive postexposure antimicrobial prophylaxis or should be monitored daily for 21 days after pertussis exposure for signs and symptoms of pertussis. The vote carried unanimously in favor of incorporating the new language.

The CDC is not obligated to follow the ACIP's suggestions, but the agency usually does.

Use of Tdap in Pregnant Women

The committee also discussed, but did not vote on, the use of Tdap in pregnant women — a group that has been excluded from randomized trials, making data unavailable in this setting. Tdap is not currently licensed for use during pregnancy, but 2 large clinical trials are ongoing, said presenter Tejpratap Tiwari, MD, from the CDC's National Center for Immunization and Respiratory Diseases.

The new ACIP wording recommends Td vaccination for booster protection against tetanus and diphtheria in pregnant women, although healthcare providers may choose to administer Tdap instead of Td during pregnancy to add protection against pertussis in special situations. In this case, "pregnant women should be informed of the lack of data confirming the safety and immunogenicity of Tdap in pregnant women," said Dr. Tiwari.

"The working group felt current strategies to prevent infant deaths were insufficient," Dr. Liang concluded. "All but one working group member felt that safety data were supportive of maternal vaccination on maternal and infant outcomes," she said. "In addition, the majority of the working group wanted to modify current recommendations, but the working group was split on the issue since the data are not conclusive."