Table 3.
ATT Estimation for Vaccination During the Follow-up Period
| Exposure Definition | Risk ratio (95% CI) | ARR (95% CI) | NNT | E-value |
| Tdap, Td, and/or TT Vaccination versus Unvaccinated | ||||
| ⩾1 Tdap or Td without TT * | 0.7059 (0.6876–0.7247) | 0.0300 (0.0277–0.0322) | 33 | 2.1848 |
| ⩾1 Tdap or Td or TT | 0.7238 (0.7055–0.7427) | 0.0302 (0.0280–0.0324) | 33 | 2.1076 |
| ⩾1 Tdap without Td and TT | 0.6804 (0.6612–0.7003) | 0.0330 (0.0306–0.0355) | 30 | 2.3004 |
| ⩾1 Td without Tdap and TT | 0.8039 (0.7533–0.8579) | 0.0198 (0.0139–0.0257) | 51 | 1.7947 |
| ⩾1 TT without Tdap and Td | 1.0495 (0.9107–1.2096) | 0.0062 (–0.0121–0.0245) | – | – |
| HZ Vaccination versus Unvaccinated | ||||
| ⩾1 Zostavax or Shingrix* | 0.7520 (0.7378–0.7666) | 0.0267 (0.0249–0.0285) | 37 | 1.9919 |
| Completed Shingrix (2 doses) without Zostavaxa | 0.2337 (0.2085–0.2619) | 0.0377 (0.0350–0.0404) | 26 | 5.8925 |
| ⩾1 Zostavax with 2 doses Shingrix | 0.1424 (0.1148–0.1766) | 0.0719 (0.0653–0.0786) | 14 | 13.5243 |
| ⩾1 Shingrix without Zostavaxa | 0.2756 (0.2550–0.2979) | 0.0385 (0.0363–0.0406) | 26 | 4.3841 |
| ⩾1 Zostavax without Shingrix | 0.9274 (0.9087–0.9466) | 0.0083 (0.0060–0.0105) | 120 | 1.3687 |
| Pneumococcal Vaccination versus Unvaccinated | ||||
| ⩾1 PCV-13 or PPSV-23* | 0.7304 (0.7186–0.7424) | 0.0297 (0.0282–0.0312) | 34 | 2.0799 |
| ⩾1 PCV-13 without PPSV-23b | 0.7319 (0.7167–0.7475) | 0.0302 (0.0281–0.0322) | 33 | 2.0736 |
| ⩾1 PPSV-23 without PCV-13 | 0.7127 (0.6940–0.7320) | 0.0295 (0.0273–0.0319) | 34 | 2.1549 |
The look back period was defined as 2009–2011 and the follow up period as 2011–2019, with the exceptions discussed below. Each analysis performed included a unique and different unvaccinated cohort. The unvaccinated cohort refers to patients who are not vaccinated with the specified vaccine for that analysis; patients may have still received other vaccinations that were not the exposure variable. For example, for the Zostavax or Shingrix vaccine analysis, the unvaccinated group would be those who received neither Zostavax nor Shingrix; however, this group could have received a Tdap/Td/TT or pneumococcal vaccine. *Denotes a main analysis. aDistinguishes that the analysis was performed using a look back period of 2009–2017 and the follow up period of 2017–2019. bCharacterizes that the analysis was performed using a look back period of 2009–2014 and the follow up period of 2014–2019. AD, Alzheimer’s disease; ARR, Absolute risk reduction; CI, Confidence Interval; HZ, Herpes zoster; ICD, International Classification of Diseases; NNT, Number needed to treat; PCV-13, pneumococcal conjugate vaccine 13; PPSV-23, Pneumococcal polysaccharide vaccine 23; Tdap, Tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis; Td, Tetanus toxoid and reduced diphtheria toxoid; TT, Tetanus toxoid.