Can an elderly patient receive the influenza (flu) and Tetanus, diphtheria, and pertussis (Tdap) vaccines on the same day?

Simultaneous Administration of Influenza and Tdap Vaccines in Elderly Patients

Yes, elderly patients can and should receive influenza and Tdap vaccines on the same day—this practice is explicitly supported by ACIP guidelines, safe, and offers practical advantages without compromising vaccine effectiveness. 1

Guideline-Based Recommendations

Inactivated influenza vaccines (IIV) and Tdap may be administered concomitantly or sequentially with other inactivated vaccines, with injectable vaccines given at separate anatomical sites. 1 This recommendation applies to all adults, including those aged ≥65 years. 1

Key Administration Principles

• Administer each vaccine using a separate syringe at different anatomic sites (e.g., one in each deltoid muscle). 1
• No minimum interval is required between administration of inactivated vaccines, making same-day administration both safe and appropriate. 1
• Tdap can be administered regardless of the interval since the most recent tetanus or diphtheria-containing vaccine. 1

Safety and Immunogenicity Evidence

The safety profile for simultaneous administration is reassuring across multiple high-quality studies:

• A randomized trial of 1,104 adults ≥65 years receiving Boostrix (Tdap) found that co-administration with influenza vaccine produced no differences in immune responses compared to sequential administration, with comparable adverse event profiles. 2
• Another randomized trial in adults aged 19-64 years demonstrated that concomitant Tdap and influenza vaccination was well tolerated, with injection-site pain (the most common adverse event) being mild and resolving by day 3 in most cases. 3
• Reassuring safety profiles have been documented for simultaneous administration of IIVs with Tdap among adults, though injection site or systemic adverse reactions may be slightly increased but are generally mild or moderate. 1

Specific Findings on Immunogenicity

• Seroprotection and seroresponse rates for all influenza strains were comparable between concomitant and sequential administration groups. 3
• For diphtheria and tetanus, seroprotection rates and post-vaccination GMTs were non-inferior with concomitant administration. 3
• A small trend toward lower antibody responses to some pertussis antigens was observed with concomitant administration, but this does not alter the recommendation given the overall clinical benefit. 3

Clinical Algorithm for Elderly Patients

Step 1: Verify Vaccination History

• Check if the patient has received Tdap previously—if not, administer Tdap now regardless of when they last received Td. 1
• If Tdap was previously given, use Td for routine 10-year boosters. 4

Step 2: Assess Influenza Vaccination Status

• Annual influenza vaccination is recommended for all persons ≥6 months of age, including elderly patients. 1
• Adults ≥65 years can receive standard-dose or high-dose inactivated influenza vaccine. 1

Step 3: Administer Both Vaccines Simultaneously

• Give both vaccines during the same visit if both are indicated and available. 5
• Use separate syringes and inject at different anatomic sites (preferably both deltoid muscles). 1, 5
• Tdap dose is 0.5 mL administered intramuscularly, preferably into the deltoid muscle. 5

Step 4: Monitor for Syncope

• Observe the patient for 15-20 minutes post-vaccination, as syncope can occur and may be more common among certain populations. 5

Common Pitfalls and Caveats

Avoid Over-Vaccination

• Do not administer tetanus boosters more frequently than every 10 years for routine immunization, as this can cause Arthus reactions (severe local hypersensitivity). 4
• The exception is wound management, where contaminated wounds may require a booster if >5 years have elapsed since the last dose. 4

Product Selection for Elderly

• When feasible, Boostrix should be used for adults ≥65 years; however, either Tdap product (Boostrix or Adacel) is immunogenic and provides protection. 4
• Do not miss vaccination opportunities—administer the Tdap product available rather than delaying vaccination. 4

Documentation

• Proper documentation of all administered vaccines is essential to prevent unnecessary revaccination. 5

Practical Advantages

Simultaneous administration increases the likelihood that patients will receive each vaccine on schedule, improving overall vaccination coverage while offering convenience and potential cost savings. 5, 3 This is particularly important for elderly patients who may have difficulty returning for multiple visits.