All medical providers in NYC were invited to order pH1N1 influenza vaccine. Providers who ordered vaccine were required to register with the CIR if they had not previously done so and to electronically sign a memorandum of agreement. Receipt of this memorandum, a faxed vaccine order form, and fulfillment of the order were recorded in the CIR. To rapidly train a large number of providers who served adult patients but had no CIR reporting experience, DOHMH provided instruction by email and through a series of webinars.

Vaccine shipments began in early October 2009. Initial doses were distributed primarily to pediatric-care providers, obstetricians, hospitals (for patients and health care workers), federally qualified health centers, and uniformed personnel (e.g., in fire and police departments). Distribution of doses to adult-care providers and DOHMH walk-in clinics began in the middle of October; most providers received doses at the end of the month. Pharmacies and residential facilities (e.g., nursing homes) began to receive vaccine in mid-December when demand was low. A portion of each weekly shipment was set aside for use in school vaccination programs and weekend point-of-dispensing clinics. Because of the limited supply, providers initially did not receive the full quantity of doses they had ordered; additional vaccine was sent as it became available.

Because vaccine supply was constantly changing and to address the many questions received from the medical community, DOHMH had to maintain continuous 2-way communication with providers throughout the entire period of vaccine allocation and distribution. To that end, the NYC Bureau of Immunization provided weekly email updates to all participating providers and posted these updates on the agency’s public website. DOHMH also held weekly conference calls with private providers, federally qualified health centers, and hospitals to provide updates and answer questions. To ensure that providers were able to contact the Bureau of Immunization with questions or concerns and to check on the status of a vaccine order, a dedicated email account was established so that inquiries could be answered within 48 hours. This email account supplemented the existing Bureau of Immunization hotline, which regularly provides information about vaccines to providers and the public; the hotline was staffed with extra personnel to handle the increased volume of calls.

Providers could report administration of pH1N1 vaccine doses in 1 of 2 ways: 1) by using the online CIR application, or 2) by sending electronic files, which conformed to a prespecified file format, directly to the CIR. Providers of child and adolescent care were expected to report administration of pH1N1 vaccine doses in the same way that they reported administration of other childhood vaccines. In addition, DOHMH designed a scannable paper reporting form for the school-based vaccination program and point-of-dispensing clinics; the completed forms were scanned, and the data were then automatically uploaded into the CIR.

From October 1, 2009, through March 4, 2010, a total of 988,298 doses of pH1N1 influenza vaccine were reported to the CIR as having been administered. These doses represented 35.5% of the 2,781,700 doses delivered to providers. Reporting to the CIR varied by provider type (Table 1). Those provider types that previously had been required to report to the CIR reported a larger proportion of the pH1N1 vaccine doses received; 53%, 46%, and 43% of total doses received by the Health and Hospitals Corporation (the NYC public hospital system), private pediatric-care providers, and federally qualified health centers, respectively, were reported. Colleges, private hospitals, and adult-care providers reported a smaller percentage of doses received: 29%, 28%, and 20%, respectively. The lowest proportion of doses reported was by residential facilities (4%) and pharmacies (0%). These provider types were the last to receive vaccine in December, when demand was very low citywide.

Because a large number of pH1N1 vaccine doses were distributed but not reported to the CIR, the Bureau of Immunization conducted a survey to estimate the number of doses actually administered by providers. The survey, which consisted of 19 questions, sought to identify how many doses providers administered and how many viable doses and expired/spoiled doses were still in stock. Providers were told the number of doses distributed to them and the number reported to the CIR. They were then asked if this was the actual number of doses given and, if not, how many more were given but not reported to the CIR. The survey also included questions about the quality of communications received from DOHMH and about providers’ experiences using the CIR.

All facilities and providers that had ordered pH1N1 vaccine from DOHMH by March 4, 2010, were eligible for inclusion in the survey. DOHMH clinics, point-of-dispensing clinics, and the school vaccination program were excluded because DOHMH conducted these operations. The complete list of potential participants was stratified into 9 groups according to facility type: private adult-care providers, private pediatric-care providers, private hospitals, colleges and universities, federally qualified health centers, the Health and Hospitals Corporation, pharmacies, residential and long-term care facilities, and uniformed personnel. A 12% computerized random sample by facility type resulted in a final pool of 395 potential participants, which included at least 1 provider from each of the 9 facility types.

DOHMH used its in-house call center to conduct the survey from March 15 through April 7, 2010. Call center staff entered responses from providers into the online survey tool Survey Monkey (www.surveymonkey.com). The survey was pre-populated with CIR data about the number of doses ordered and administered by the facility. The Bureau of Immunization trained the call center staff and provided background information on pH1N1 vaccination, DOHMH vaccine distribution methods, and CIR reporting methods. Up to 4 calls were made to each of the selected sites during March and April 2010. After 4 unanswered calls or refusal to participate, facilities were considered nonresponders. The survey took ≈5 minutes to complete.

Of the 395 facilities sampled, 228 completed the survey (58% response rate) (Table 2). Nearly all providers acknowledged that they did not report a portion of administered doses to the CIR; across all provider groups, 9,297 (8%) of the 116,600 doses received by facilities that responded to the survey were reported as administered but not reported to the CIR. Reporting was achieved across provider types: 79% of private pediatric-care providers, 49% of adult-care providers, and 44% of residential facilities surveyed reported at least some of the administered doses to the CIR.

For most providers, a large proportion of vaccine remained in storage in their facilities as either viable or expired/spoiled. Among all providers surveyed, nearly 27,812 doses (24% of doses received) remained at the facilities. In addition, 40,069 doses (34% of doses received) were unaccounted for, meaning that they were not reported to the CIR or through the survey as administered and not reported as remaining in storage or expired/spoiled.

If the number of doses the surveyed providers reported that they administered is considered to be a reasonable estimate of the true number of doses administered, then 81% of all doses administered were reported to the CIR. Among private noninstitutional providers, pediatric-care providers reported 93% of all doses administered and adult-care providers reported 59% of all doses administered.

To assess potential discrepancies between the number of pH1N1 vaccine doses reported and the number actually administered by each surveyed provider type, we linked survey data to CIR data. The number of doses administered by survey respondents was calculated by aggregating 1) the total number of doses reported to the CIR for each provider group and 2) the total number of doses reported as administered but not reported to the CIR by that group. The reporting rate (number of doses reported to the CIR divided by the number of doses administered, both those reported to the CIR and those reported as administered but not reported by the provider) was then calculated for each provider group. To estimate the number of doses administered but not reported to the CIR by each provider group, we then applied these rates to the citywide population of providers in each group. These numbers were tallied for an estimate of the total number of doses administered citywide. The analysis was based on vaccine doses administered, not on the number of persons vaccinated. Citywide rates for each provider type were weighted by the number of doses received by each provider type group and then averaged to calculate an overall reporting rate. Frequencies were calculated for responses to questions about the vaccine ordering process and DOHMH communications by facility type.

We estimated that as of March 4, 2010, a total of 1,160,587 doses of pH1N1 vaccine were administered (vs. 988,298 doses reported to CIR) citywide. This number represents 42% of all doses delivered to providers. According to the survey results, an estimated 568,561 doses remained in providers’ offices (viable and/or expired/spoiled) and ≈1 million (36%) of the 2.78 million doses distributed were unaccounted for. If these doses had actually been administered, the number of doses administered could be as high as 2.16 million.

Nearly all (96%) providers surveyed found the weekly updates on vaccine ordering and reporting sent by DOHMH to be helpful (Table 3). The percentages of providers reporting problems were 10% for enrolling in the CIR, 3% for completing and submitting the provider agreement, 9% for ordering pH1N1 vaccine, 1% for administering pH1N1 vaccine to patients, and 12% for reporting doses to the CIR (Table 4).The greatest difficulties were encountered by the 9 residential facilities surveyed; 11% reported problems with registration, and 22% reported problems with reporting doses to the CIR (Table 4).