This study is a small-scale randomized, placebo-controlled factorial trial of two interventions to increase Tetanus, diphtheria and acellular pertussis (Tdap) immunization rates among infant caregivers. Specifically, the trial will compare a full cost vs. $5 Tdap voucher with or without an educational video.

The incidence of pertussis, a highly contagious respiratory illness, has more than tripled in the past five years, and is on track this year to be the most severe in over a half century. Pertussis is particularly dangerous, and commonly fatal, for young infants who have not completed the primary vaccination series. To protect infants, pregnant women and adult caregivers should receive Tdap vaccination, but coverage is estimated at only 10% for adult caregivers in close contact with infants.

The objective of this study is to conduct a small-scale randomized controlled trial of an intervention to increase Tdap immunization rates among infant caregivers. The intervention is delivered at the newborn primary care visit and consists of two components: (1) Tdap vaccine vouchers redeemable at neighborhood retail pharmacies and (2) video-based education. The vouchers improve vaccine supply by reducing cost and improving accessibility of the vaccine, while the education component increases demand for the vaccine by making salient the dangers of pertussis and the importance adult vaccination to "cocoon" vulnerable infants. We will evaluate the feasibility and acceptability of each component or both compared to none and assess the impact on the vaccination of parents/caregivers of newborn infants.

Recruitment for this pilot study will take place at a pediatric primary care practice site affiliated with a large children's hospital in Philadelphia, Pennsylvania (PA). The practice schedules approximately 135 newborn visits per month, typically at 2-14 days of life. Participants will redeem Tdap vaccine vouchers at 2 local Rite Aid pharmacies which are the closest Rite Aid locations to the clinic site. The pharmacy accepts all major insurance plans, although most plans (including Medicaid) do not cover Tdap vaccine delivered in pharmacies.

All caregivers ≥ 18 years old who accompany an infant to a newborn visit will be approached by the study coordinator and details of the study will be explained. Caregivers will be asked to participate in the study and if interested, informed consent will be obtained before any study related procedures are performed. Potential subjects will then be screened using the protocol inclusion and exclusion criteria. The research assistant will utilize a data collection form to collect demographic data. After completion of the data collection form, participants will view an educational video if randomized to the education arm. After viewing the educational video, or after completion of data collection form for those who were not randomized to video, participants will receive an envelope containing the Tdap and baby care item voucher or gift card.

Unvaccinated caregivers will receive an envelope containing 2 vouchers or a voucher and a gift card. The vouchers are: one for Tdap vaccination and one for a baby care item. Vouchers will be redeemable only at the two participating nearby Rite Aid pharmacies, will have no monetary value, and cannot be redeemed for any items other than the specified vaccine/baby care product.The gift card can be redeemed at any Rite Aid pharmacy.All envelopes will also contain the Center for Disease Control and Prevention (CDC) Vaccine Information Sheet (V.I.S) for the Tdap vaccine. Participants will be randomized to receive either: (1) a voucher for the full price of a Tdap vaccine ($63.99) + a baby care product voucher/or gift card, or (2) a voucher for $5 off a Tdap vaccine + a baby care product voucher/or gift card. The baby care product voucher / gift card will allow us to assess the proportion of respondents who make a trip to one of the pharmacies following the primary care visit and may also increase the probability that the study participants will visit one of the designated retail pharmacies. The full cost voucher removes any cost barriers related to the Tdap vaccine. The $5 voucher allows us to assess the effect of increased awareness, convenience, and accessibility on vaccine uptake, but without a significant price change. If two unvaccinated caregivers accompany an infant and both choose to enroll in the study, they may receive discordant Tdap voucher amounts; however, both will receive baby care product vouchers / gift cards.

Randomization to each arm will occur through block randomization of study numbers that will take place prior to recruitment. The research assistants will show the video and will therefore not be blinded to educational arm. However, research assistants who enroll participants will be blinded to voucher arm as envelopes will be sealed. Research staff will enter the study number on the data collection form but only the principal investigator and study coordinator will have access to the master file indicating allocation to intervention group.

Voucher redemption is voluntary; data regarding vaccination redemption will be collected by Rite Aid pharmacies. Participants who choose to redeem Tdap vaccine vouchers can do so, at their convenience, at 2 local Rite Aid pharmacies. At the pharmacy, the caregiver must complete a screening form before receiving Tdap. Vouchers are serialized with a barcode which is swiped at the time of redemption Baby care item vouchers will be like a coupon and can be redeemed by a cashier at the pharmacy.

Project staff will perform phone follow-up interviews with participants one month after they were enrolled in the study to ascertain vaccination status and to solicit feedback on the intervention and barriers to vaccination.

Baseline characteristics will be summarized by standard descriptive summaries (e.g. means and standard deviations for continuous variables and percentages for categorical variables). All vouchers will have unique identification (ID) numbers. Variables such as age, gender, insurance status, the relationship of the participant(s) to the infant, vaccination status, and the date and time of the voucher distribution will be summarized. The research coordinator will also record how many caregivers refuse to participate or are not approached for enrollment. The proportion of caregivers screened that meet enrollment criteria and the proportion meeting enrollment criteria that consent to participate will be calculated.

We will measure the proportion of participants enrolled that redeemed a study Tdap voucher. In addition, we will assess the feasibility of voucher distribution, the completeness of redemption data recorded at the pharmacy, and the ability to assess caregiver vaccination status. Vaccination status will be determined by self-report at the time of enrollment and at the time of the follow-up interview. Vaccination rates will also be measured by Tdap voucher redemption. We will measure the redemption rate of the Tdap voucher by treatment arm ($5 voucher vs. full-cost voucher, and video vs. no video), adjusting for sociodemographic characteristics. We will also determine the proportion of baby care product vouchers / gift cards redeemed by treatment arm.

Inclusion Criteria:

1. All caregivers who report that they have never received Tdap
2. Mothers who did not receive Tdap during their most recent pregnancy or since the birth of the child, even if she received Tdap during a previous pregnancy, as Tdap is now recommended for all pregnant women during each pregnancy.
3. Previous receipt of a tetanus containing vaccine (i.e. Td or TT), regardless of the time interval since receipt of the tetanus-containing vaccine will be also eligible for the study.
4. If a participant is certain they have not received Tdap within the past year but uncertain whether he/she has ever received Tdap, we will offer enrollment and encourage participants to obtain immunization records to confirm their status before voucher redemption. Rite Aid will follow their screening procedures which also includes assessing immunization status. Participants who do not know their Tdap vaccination status will receive the voucher intervention.

Exclusion Criteria:

1. Any adult caregiver who has previously received Tdap
2. For recently-pregnant women: If a mother who received Tdap during her most recent pregnancy (2nd trimester or 3rd trimester) or since the birth of the child. Also, if the mother is unsure of her vaccination status and possibly received the vaccine during this pregnancy or in the last year