Assessing the number of antigens received per visit and frequency of vaccination visits among children 16-19 months of age, IIS sentinel sites, 2004-2008 Good morning, as Jim mentioned, I am Diana Bartlett. I manage a CDC funded project called the Immunization Information Systems Sentinel Site project. It’s a vaccination surveillance demonstration project that utilizes IIS data for vaccination coverage assessment and program evaluation. Last summer, the National Vaccine Program Office (NVPO) asked us to help them answer a few questions and I’ll be sharing some of our results with you today. Diana Bartlett and Laura Williams NCIRD/Immunization Services Division Immunization Information Systems Support Branch

Objectives Describe how children are getting vaccinated, by number of antigens received at each visit and number of vaccine visits. Analysis includes measuring the impact of addition of rotavirus and HepA to the vaccine schedule. Are parents spacing out vaccine visits more? The NVPO essentially wanted to know if parental concerns over the number of vaccines or vaccine safety was causing them to space out the number of visits for their children and the number of vaccines received at a visit. Since IIS can provide timely data, we not only looked to see if children were up-to-date with the standard vaccine series but also to see how the addition of rotavirus and the new recommendations for Hepatitis A would affect vaccination patterns.

IIS Sentinel Sites Project Assesses vaccination coverage for persons aged <19 years Implement enhanced data quality procedures Usually a subset of the state IIS coverage area with contiguous geographic counties, postal code areas, or census tracts At a minimum, sites need to have: At least 85% vaccine provider sites enrolled in the IIS; At least 85% of the children <19 years of age in the population with at least 2 vaccinations recorded in the IIS At least 70% of the doses administered from this sentinel site area should be submitted to and processed by the IIS within 30 days of vaccine administration. Just so you have a little bit of background on our data source, the IIS sentinel site project includes 8 CDC immunization grantees who have chosen a subset of their state or city IIS for analysis. The data analysis is also limited to persons <19 years of age, uses enhanced data quality procedures in these areas, and has at least 85% child and provider participation in the area with the majority of vaccination data processed by the IIS within 30 days.

IIS Sentinel Site Profiles Geographic Area # of Children <6 yrs old enrolled in IIS and living in sentinel site area % children <19 years old in population with ≥2 doses in IIS % of enrolled provider sites % vaccinations recorded in the IIS within 30 days AZ Seven counties in northern AZ 72,686 87% 99% 73% CO 14 counties in southwestern CO 13,207 90% 98% 92% MI 81/83 counties in state 546,594 100% 95% MN Hennepin County (Minneapolis) 105,754 85% 81% NYC Manhattan, Bronx, Brooklyn, Staten Island, Queens 754,942 75% ND Entire state 55,962 96% OR Washington and Multnomah counties (greater Portland) 102,870 97% 94% 82% WI 5 counties in southern WI (includes Madison) 85,836 77% This slide just demonstrates the diversity among the sites. They are not nationally representative. The eight participating grantees include Arizona, Colorado, Michingan, Minnesota, New York City, North Dakota, Oregon, and Wisconsin. Although New York City and North Dakota use their entire geographic area for analysis, grantees like Oregon limit their analysis to the greater Portland area and Arizona focuses on the northern part of the state.

Study Methods (1) Cohort 1: Children born from August 1, 2004-November 30, 2004 (16-19 months of age) Fully vaccinated= 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, and 1 varicella vaccine Vaccines administered no later than March 30, 2006 Cohort 2: Children born from August 1, 2006-November 30, 2006 (16-19 months of age) Fully vaccinated= 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, 1 varicella, 3 rotavirus, and 1 Hep A Vaccines administered no later than March 30, 2008 Considerations in data interpretation: April 2006: Rotavirus vaccine joined the VFC contract (ACIP recommended February 2006) May 2006: Hep A recommendations to routinely vaccinate 12-23 month olds December 2007: Hib vaccine shortage To demonstrate the influence of rotavirus and Hepatitis on any new vaccination patterns, we looked at two cohorts of children. We focused our questions on children who were 16-19 months of age as of the spring of 2008 (named Cohort 2 for children born in the fall of 2006) and compared that to an earlier cohort of children in that age group born in the fall of 2004 (who will we name Cohort 1). To be fully vaccinated in cohort 1, a children needed 3 doses of DTP vaccine, 2 doses of polio, 1 MMR, 3 doses of Hib, 2 doses of Hep B, 4 doses of pneumococcal conjugate vaccine, and 1 dose of varicella vaccine as of 16 months of age. To be fully vaccinated in cohort 2, you needed the same vaccines as in cohort 1 but with the addition of 3 doses of the rotavirus vaccine and 1 dose of Hepatitis A. Right from the beginning, we would have to keep a few things in mind with our interpretation of results. Our cohort 2 children were born from August –November 2006. The rotavirus vaccine joined the Vaccines for Children contract in April 2006 and many states did not get their first shipments of the VFC rotavirus vaccine until the fall 2006, so it’s likely that not all of the children born in the fall 2006 would have the same opportunity to get three doses of the vaccine. Also, we looked at vaccinations as of 16 months of age and children are recommended to receive their first dose of Hepatitis A anytime between 12-23 months of age, so many children may have ultimately received the dose within the proper interval, but just not within the time frame of this study.

Study Methods (2) Well-child visits had a +/- 7 day grace period around 2 month, 4 month, etc. birthdays Extra-immunizations were included but travel vaccines, rabies, and influenza vaccines were excluded Analysis excluded CO because it had very small numbers Analysis focused on # of antigens administered by age group, well-child visit, the number of vaccination visits by age group, total number of visits by vaccination status and cohort We analyzed data to see if children were getting their vaccines on their well child visits and defined the well child visits as any vaccination visit within one week prior or one week after a child’s 2 month, 4 month, 6 month, etc. birthdays. We focused our analysis to the vaccines in the fully-vaccinated definition and excluded travel vaccines, rabies vaccine, etc. Except for my next two slides which show results by grantee, most slides have an unweighted mean percentage of seven of the grantees. CO’s numbers were excluded from the analysis because their numbers were very, very small. Time restraints prevent me from presenting all of our results, but the analysis focused on the number of antigens administered by age group, well-child visit, the number of vaccination visits by age group, and the total number of visits by vaccination status and cohort

Percent of children 16-19 months of age by vaccination status and cohort Number of children 16-19 months of age in IIS by cohort % Fully Vaccinated % Partially Vaccinated* Site Cohort 1 (N) Cohort 2 AZ 4,066 4,322 40.5 14.6 57.1 84.7 MI 29,712 30,140 45.4 12.9 51.4 84.1 MN 5,959 6,084 40.7 20.7 45.2 69.5 ND 3,108 3,251 46.8 15.3 49.4 83.0 NYC 52,301 51,684 12.1 3.9 70.8 86.4 OR 5,523 5,974 34.8 7.0 55.0 86.1 WI 4,804 4,789 51.2 16.5 43.0 80.8 This slide shows the differences between Cohort 1 and Cohort 2 by the percentage of children 16-19 months of age by vaccination status. Let’s look at Wisconsin, which is the last row of the table, as an example. Both cohorts had roughly the same number of children in the analysis (about 4800 children), but when you add rotavirus and Hep A vaccine to the fully-vaccinated definition, you see that only about 16% of the children were fully vaccinated compared to 50% of the children in cohort 1. *Partially vaccinated excludes unvaccinated. The percentage of unvaccinated children ranged from 2.4%-17.0% in Cohort 1 and 0.7%-9.8% in Cohort 2.

Percent of children 16-19 months of age fully vaccinated when Cohort 2 excludes Hep A and RotaTeq Number of children 16-19 months of age in IIS by cohort % Fully Vaccinated % Partially Vaccinated* Site Cohort 1 (N) Cohort 2 AZ 4,066 4,322 38.6 33.6 54.1 61.0 MI 29,712 30,140 45.4 45.6 51.4 51.5 ND 3,108 3,251 46.8 37.2 49.4 61.2 NYC 52,301 51,684 12.1 15.0 70.8 75.0 OR 5,523 5,974 34.8 39.7 55.0 53.4 WI 4,804 4,789 51.2 46.3 43.0 50.1 Looking at WI again in the last row as our example, when we remove rotavirus and Hep A vaccine from our fully-vaccinated definition, we see that the two cohorts had roughly the same percentage of fully vaccinated children. *Partially vaccinated excludes unvaccinated. The percentage of unvaccinated children ranged from 2.4%-14.1% in Cohort 1 and 0.7%-9.7% in Cohort 2. AZ varies in Cohort 1 numbers.

Total number of vaccine visits among fully-vaccinated children by 16 months of age and cohort Despite the addition of four more vaccines to the fully vaccinated definition in Cohort 2, we see that in both cohorts, most of the fully-vaccinated children became fully-vaccinated within 5-6 visits. Some grantees had children who became done as early as their 4th vaccine visit, but some children took as many as 10 visits to become up-to-date. Cohort 1: Children born from August 1, 2004-November 30, 2004 who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, and 1 varicella vaccine. Vaccines administered no later than March 30, 2006. Cohort 2: Children born from August 1, 2006-November 30, 2006. who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, 1 varicella, 3 rotavirus, and 1 Hep A. Vaccines administered no later than March 30, 2008.

Total number of vaccine visits among partially-vaccinated children by 16 months of age and cohort As expected, the partially vaccinated children had a more scattered vaccination pattern, although about half of the children in Cohort 2 (the green bars) had 5-6 vaccine visits to yet did not become up-to-date within those visits. Cohort 1: Children born from August 1, 2004-November 30, 2004 who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, and 1 varicella vaccine. Vaccines administered no later than March 30, 2006. Cohort 2: Children born from August 1, 2006-November 30, 2006. who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, 1 varicella, 3 rotavirus, and 1 Hep A. Vaccines administered no later than March 30, 2008.

Number of antigens administered at the 2-month visit among children fully vaccinated by 16 months of age When you look at vaccination patterns during what we have defined to be the well child visits, we see that most of the children in Cohort 1 (in yellow) received 7 antigens while Cohort 2 (in green) received mostly 8 antigens. We assume that one dose of rotavirus is making the difference here. Although on the far left it looks like there are 25-30% of children not receiving any vaccine at this visit, we must keep in mind that this is likely a reflection of the child just not getting their vaccines during the two week window we have defined as the well-child visit. They may have still received vaccines within their 2nd month of life. Cohort 1: Children born from August 1, 2004-November 30, 2004 who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, and 1 varicella vaccine. Vaccines administered no later than March 30, 2006. Cohort 2: Children born from August 1, 2006-November 30, 2006. who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, 1 varicella, 3 rotavirus, and 1 Hep A. Vaccines administered no later than March 30, 2008.

Number of antigens administered at the 4-month visit among children fully vaccinated by 16 months of age We see the same pattern in at the 4 month visit. Cohort 1: Children born from August 1, 2004-November 30, 2004 who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, and 1 varicella vaccine. Vaccines administered no later than March 30, 2006. Cohort 2: Children born from August 1, 2006-November 30, 2006. who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, 1 varicella, 3 rotavirus, and 1 Hep A. Vaccines administered no later than March 30, 2008.

Number of antigens administered at the 6-month visit among children fully vaccinated by 16 months of age Now with the 6 month visit, we see a more varied pattern. In Cohort 2, about 35-40% of the children are still getting 7-8 vaccines during the 6 month well child visit, but an equal number are not getting any vaccines during this two-week window. Cohort 1: Children born from August 1, 2004-November 30, 2004 who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, and 1 varicella vaccine. Vaccines administered no later than March 30, 2006. Cohort 2: Children born from August 1, 2006-November 30, 2006. who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, 1 varicella, 3 rotavirus, and 1 Hep A. Vaccines administered no later than March 30, 2008.

Number of antigens administered from 6-11 Number of antigens administered from 6-11.9 months of age among children fully vaccinated by 16 months of age If we look at this more closely and look at the age in which the child received their vaccines, say from 6 months to just before the 12 month of life, we can see that in Cohort 2 almost 70% of the children are receiving 7-8 antigens within this age window. Cohort 1: Children born from August 1, 2004-November 30, 2004 who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, and 1 varicella vaccine. Vaccines administered no later than March 30, 2006. Cohort 2: Children born from August 1, 2006-November 30, 2006. who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, 1 varicella, 3 rotavirus, and 1 Hep A. Vaccines administered no later than March 30, 2008.

Number of antigens administered at the 12-month visit among children fully vaccinated by 16 months of age During the 12 month month well-child visit, we see a similar scattered pattern with just under 40% of the Cohort 2 children receiving mostly 5-6 antigens at this visit and about 45% of the children not receiving any vaccines during this two-week window. Cohort 1: Children born from August 1, 2004-November 30, 2004 who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, and 1 varicella vaccine. Vaccines administered no later than March 30, 2006. Cohort 2: Children born from August 1, 2006-November 30, 2006. who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, 1 varicella, 3 rotavirus, and 1 Hep A. Vaccines administered no later than March 30, 2008.

Number of antigens administered from 12-14 Number of antigens administered from 12-14.9 months of age among children fully vaccinated by 16 months of age However, when we expand our analysis to see the number of antigens received from 12 months to just before the 15 month well child visit, we see that many of these children are getting 5-6 antigens or more. Cohort 1: Children born from August 1, 2004-November 30, 2004 who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, and 1 varicella vaccine. Vaccines administered no later than March 30, 2006. Cohort 2: Children born from August 1, 2006-November 30, 2006. who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, 1 varicella, 3 rotavirus, and 1 Hep A. Vaccines administered no later than March 30, 2008.

Number of antigens administered at the 15-month visit among children fully vaccinated by 16 months of age Vaccine administration seems to be even more spread out at the 15 month visit with as many as 60% of the children not receiving any vaccine within this 2 week window. Cohort 1: Children born from August 1, 2004-November 30, 2004 who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, and 1 varicella vaccine. Vaccines administered no later than March 30, 2006. Cohort 2: Children born from August 1, 2006-November 30, 2006. who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, 1 varicella, 3 rotavirus, and 1 Hep A. Vaccines administered no later than March 30, 2008.

Number of antigens administered from 15-15 Number of antigens administered from 15-15.9 months of age among children fully vaccinated by 16 months of age When we expand the vaccination window to just before the 16 month, we see that receiving 4-5 antigens is more common, but that the 15 month visit, as expected, is mostly a catch-up visit for vaccines that were not administered within the 12-14.9 month window. Cohort 1: Children born from August 1, 2004-November 30, 2004 who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, and 1 varicella vaccine. Vaccines administered no later than March 30, 2006. Cohort 2: Children born from August 1, 2006-November 30, 2006. who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, 1 varicella, 3 rotavirus, and 1 Hep A. Vaccines administered no later than March 30, 2008.

Limitations Incomplete reporting of varicella (12-18 months recommended administration) and Hep A (12-23 month recommended vaccination administration in Cohort 2) due to vaccination coverage assessment as of 16 months Availability of VFC rotavirus vaccine in provider offices Provider participation may not be sufficiently high in areas of interest and may not fully reflect all types of providers administering vaccines Estimates may be affected by enrollees’ mobility within state & in/out sentinel site area Data may not be adequately de-duplicated (e.g., multiple records may exist for one child) As with any study, we have some limitations. The timing of the study to meet the needs of the NVPO limited our analysis to vaccinations administered by 16 months of age which contributed to incomplete reporting of Hepatitis A, rotavirus vaccine, and even varicella which has a recommended interval of 12-18 months. A concurrent analysis using 2006 National Immunization Survey data found that 21% of varicella doses were administered from 15-19 months of age. Although the IIS sentinel sites have high provider participation and enhanced data quality protocols, there is not 100% of provider participation in all sites and data quality can always be improved.

Summary In both cohorts, 75-80% of fully vaccinated children had 5-6 visits compared to ~50% of the partially vaccinated children. Fully vaccinated children were more likely to have milestone age visits at 2 and 4 months of age RotaTeq and Hep A did not increase the number of vaccination visits Children received on average one additional antigen per vaccination visit during the first 12 months The decrease in fully vaccinated children in Cohort 2 is likely due to them not receiving Hep A by 16 months or having VFC rotavirus vaccine in wide distribution In summary, in both cohorts, the majority of children became fully-vaccinated within 5-6 visits. Half of the partially vaccinated children in either cohort also had 5-6 vaccination visits, so there appears to be some missed opportunities for vaccination in this group. The well-child visits at 2 and 4 months were focused towards immunizations with more scattered vaccination patterns in the older well-child visits. The four additional doses of vaccine needed in Cohort 2 did not seem to affect the number of vaccine visits but simply added an additional antigen per vaccination visit on average during the first 12 months of life. The decrease in fully vaccinated children in Cohort 2 is likely due to the children not receiving Hep A and varicella within our cut-off of 16 months as well as the limited distribution of VFC rotavirus vaccine during our study time period.

Acknowledgments Sentinel site colleagues: Arizona Department of Health Services: Kathy Fredrickson, MS, MPH and Lisa Rasmussen Colorado Department of Public Health and Environment Immunization Program: Elaine Lowery, JD, MA, MSPH and Kellyn Pearson, RN, BSN, MSN, CPNP Michigan Department of Community Health: Therese Hoyle and Kyle Enger, MPH Minnesota Department of Health : Karen E. White, MPH and Emily J. Peterson North Dakota Department of Health: Molly Sander, MPH New York City Department of Health and Mental Hygiene: Vikki Papadouka, PhD, MPH and Michael Andreas Hansen, MPH Oregon Immunization Program, Public Health Division, DHS: James A. Gaudino, Jr., MD, MS, MPH and Mary Beth Kurilo, MPH Wisconsin Immunization Program: Thomas Maerz and Stephanie Schauer

Diana Bartlett, MPH dbartlett@cdc.gov Questions? Diana Bartlett, MPH dbartlett@cdc.gov

Extra slides

Number of antigens administered from 0-1 Number of antigens administered from 0-1.9 months of age among children fully vaccinated by 16 months of age Cohort 1: Children born from August 1, 2004-November 30, 2004 who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, and 1 varicella vaccine. Vaccines administered no later than March 30, 2006. Cohort 2: Children born from August 1, 2006-November 30, 2006. who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, 1 varicella, 3 rotavirus, and 1 Hep A. Vaccines administered no later than March 30, 2008.

Number of antigens administered from 2-3 Number of antigens administered from 2-3.9 months of age among children fully vaccinated by 16 months of age Cohort 1: Children born from August 1, 2004-November 30, 2004 who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, and 1 varicella vaccine. Vaccines administered no later than March 30, 2006. Cohort 2: Children born from August 1, 2006-November 30, 2006. who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, 1 varicella, 3 rotavirus, and 1 Hep A. Vaccines administered no later than March 30, 2008.

Number of antigens administered from 4-5 Number of antigens administered from 4-5.9 months of age among children fully vaccinated by 16 months of age Cohort 1: Children born from August 1, 2004-November 30, 2004 who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, and 1 varicella vaccine. Vaccines administered no later than March 30, 2006. Cohort 2: Children born from August 1, 2006-November 30, 2006. who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, 1 varicella, 3 rotavirus, and 1 Hep A. Vaccines administered no later than March 30, 2008.

Number of antigens administered from 6-11 Number of antigens administered from 6-11.9 months of age among children fully vaccinated by 16 months of age Cohort 1: Children born from August 1, 2004-November 30, 2004 who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, and 1 varicella vaccine. Vaccines administered no later than March 30, 2006. Cohort 2: Children born from August 1, 2006-November 30, 2006. who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, 1 varicella, 3 rotavirus, and 1 Hep A. Vaccines administered no later than March 30, 2008.

Number of antigens administered from 12-14 Number of antigens administered from 12-14.9 months of age among children fully vaccinated by 16 months of age Cohort 1: Children born from August 1, 2004-November 30, 2004 who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, and 1 varicella vaccine. Vaccines administered no later than March 30, 2006. Cohort 2: Children born from August 1, 2006-November 30, 2006. who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, 1 varicella, 3 rotavirus, and 1 Hep A. Vaccines administered no later than March 30, 2008.

Number of antigens administered from 15-15 Number of antigens administered from 15-15.9 months of age among children fully vaccinated by 16 months of age Cohort 1: Children born from August 1, 2004-November 30, 2004 who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, and 1 varicella vaccine. Vaccines administered no later than March 30, 2006. Cohort 2: Children born from August 1, 2006-November 30, 2006. who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, 1 varicella, 3 rotavirus, and 1 Hep A. Vaccines administered no later than March 30, 2008.

# of antigens received by fully-vaccinated children by cohort Note: Estimate that Cohort 1 children should have received 24-26 antigens to be UTD while Cohort 2 children should have received 28-30 antigens. Pattern represents children getting UTD earlier than expected by 16 months, not extra-immunization.

# of doses needed for partially-vaccinated children to be fully vaccinated Cohort 1: Children born from August 1, 2004-November 30, 2004 who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, and 1 varicella vaccine. Vaccines administered no later than March 30, 2006. Cohort 2: Children born from August 1, 2006-November 30, 2006. who received 3 doses DTP, 2 polio, 1 MMR, 3 Hib, 2 Hep B, 4 PCV, 1 varicella, 3 rotavirus, and 1 Hep A. Vaccines administered no later than March 30, 2008.