Influenza Vaccine Effectiveness Estimates among US Department of Defense Adult Beneficiaries over Four Consecutive Influenza Seasons: A Test-Negative Design Study with Different Control Groups
Abstract
:1. Introduction
2. Methods
2.1. Study Population
2.2. Age Stratification
2.3. Statistical Analysis
3. Results
3.1. Patient Characteristics
3.2. Confounding Factors Assessment
3.3. Overall VE
3.4. VE by Age Groups
3.5. Influenza Vaccination Coverage
4. Discussion
5. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
Disclaimer
References
- Centers for Disease Control and Prevention. People at High Risk for Flu Complications: Flu & People 65 Years and Older. Available online: https://www.cdc.gov/flu/highrisk/65over.htm (accessed on 20 November 2021).
- Coleman, R.; Eick-Cost, A.; Hawksworth, A.W.; Hu, Z.; Lynch, L.; Myers, C.A.; DeMarcus, L.; Federinko, S. Department of Defense end-of-season influenza vaccine effectiveness estimates for the 2017–2018 season. MSMR 2018, 25, 16–20. [Google Scholar] [PubMed]
- Shoubaki, L.A. Department of Defense global, laboratory-based influenza surveillance program’s influenza vaccine effectiveness estimates and surveillance trends for 2016–2017 influenza season. MSMR 2018, 25, 8–9. [Google Scholar] [PubMed]
- Hu, W.; Gruner, W.E.; DeMarcus, L.S.; Thervil, J.W.; Kwaah, B.; Fries, A.C.; Sjoberg, P.A.; Robbins, A.S. Influenza surveillance trends and influenza vaccine effectiveness among Department of Defense beneficiaries during the 2019–2020 influenza season. MSMR 2021, 28, 2–8. [Google Scholar]
- Kersellius, G.D.; Gruner, W.E.; Fries, A.C.; DeMarcus, L.S.; Robbins, A.S. Respiratory pathogen surveillance trends and influenza vaccine effectiveness estimates for the 2018–2019 season among Department of Defense beneficiaries. MSMR 2020, 27, 17–23. [Google Scholar]
- Feng, S.; Fowlkes, A.L.; Steffens, A.; Finelli, L.; Cowling, B.J. Assessment of virus interference in a test-negative study of influenza vaccine effectiveness. Epidemiology 2017, 28, 514–524. [Google Scholar] [CrossRef] [PubMed]
- Feng, S.; Cowing, B.J.; Kelly, H.; Sullivan, S.G. Estimating influenza vaccine effectiveness with the test-negative design using alternative control groups: A systematic review and meta-analysis. Am. J. Epidemiol. 2018, 187, 389–397. [Google Scholar] [CrossRef]
- Wu, A.; Mihaylova, V.T.; Landry, M.L.; Foxman, E.F. Interference between rhinovirus and influenza A virus: A clinical data analysis and experimental infection study. Lancet Microbe 2020, 1, e254–e262. [Google Scholar] [CrossRef]
- Pierse, N.; Kelly, H.; Thompson, M.G.; Bissielo, A.; Radke, S.; Sue Huang, Q.; Baker, M.G.; Turner, N.; on behalf of the SHIVERS Investigation Team. Influenza vaccine effectiveness for hospital and community patients using control groups with and without non-influenza respiratory viruses detected, Auckland, New Zealand 2014. Vaccine 2016, 34, 503–509. [Google Scholar] [CrossRef]
- Van Doorn, E.; Darvishian, M.; Dijkstra, F.; Donker, G.A.; Overduin, P.; Meijer, A.; Hak, E. Influenza vaccine effectiveness estimates in the Dutch population from 2003 to 2014: The test-negative design case-control study with different control groups. Vaccine 2017, 35, 2831–2839. [Google Scholar] [CrossRef]
- Grohskopf, L.A.; Alyanak, E.; Broder, K.R.; Blanton, L.H.; Fry, A.M.; Jernigan, D.B.; Atmar, R.L. Prevention and control of seasonal influenza with vaccines: Recommendations of the Advisory Committee on Immunization Practices—United States, 2020–2021 influenza season. MMWR Recomm. Rep. 2020, 69, 1–24. [Google Scholar] [CrossRef]
- Hu, W.; DeMarcus, L.S.; Sjoberg, P.A.; Robbins, A.S. Inactivated influenza vaccine effectiveness among Department of Defense beneficiaries aged 6 months–17 years, 2016–2017 through 2019–2020 influenza seasons. PLoS ONE 2021, 16, e0256165. [Google Scholar] [CrossRef]
- Belongia, E.A.; Simpson, M.D.; King, J.P.; Sundaram, M.E.; Kelley, N.S.; Osterholm, M.T.; McLean, H.Q. Variable influenza vaccine effectiveness by subtype: A systematic review and meta-analysis of test-negative design studies. Lancet Infect. Dis. 2016, 16, 942–951. [Google Scholar] [CrossRef]
- Russell, K.; Chung, J.R.; Monto, A.S.; Martin, E.T.; Belongia, E.A.; McLean, H.Q.; Gaglani, M.; Murthy, K.; Zimmerman, R.K.; Nowalk, M.P.; et al. Influenza vaccine effectiveness in older adults compared with younger adults over five seasons. Vaccine 2018, 36, 1272–1278. [Google Scholar] [CrossRef] [PubMed]
- Flannery, B.; Chung, J.R.; Monto, A.S.; Martin, E.T.; Belongia, E.A.; McLean, H.Q.; Gaglani, M.; Murthy, K.; Zimmerman, R.K.; Nowalk, M.P.; et al. Influenza vaccine effectiveness in the United States during the 2016–2017 season. Clin. Infect. Dis. 2019, 68, 1798–1806. [Google Scholar] [CrossRef] [PubMed]
- Flannery, B.; Garten Kondor, R.J.; Chung, J.R.; Gaglani, M.; Reis, M.; Zimmerman, R.K.; Nowalk, M.P.; Jackson, M.L.; Jackson, L.A.; Monto, A.S.; et al. Spread of antigenically drifted influenza A(H3N2) viruses and vaccine effectiveness in the United States during the 2018–2019 season. J. Infect. Dis. 2020, 221, 8–15. [Google Scholar] [CrossRef] [PubMed]
- Rolfes, M.A.; Flannery, B.; Chung, J.R.; O’Halloran, A.; Garg, S.; Belongia, E.A.; Gaglani, M.; Zimmerman, R.K.; Jackson, M.L.; Monto, A.S.; et al. Effects of influenza vaccination in the United States during the 2017–2018 influenza season. Clin. Infect. Dis. 2019, 69, 1845–1853. [Google Scholar] [CrossRef] [PubMed] [Green Version]
- Mameli, C.; D’auria, E.; Erba, P.; Nannini, P.; Zuccotti, G.V. Influenza vaccine response: Future perspectives. Expert Opin. Biol. Ther. 2018, 18, 1–5. [Google Scholar] [CrossRef] [PubMed] [Green Version]
- Crooke, S.N.; Ovsyannikova, I.G.; Poland, G.A.; Kennedy, R.B. Immunosenescence and human vaccine immune responses. Immun. Ageing 2019, 16, 25. [Google Scholar] [CrossRef] [PubMed] [Green Version]
- Sullivan, S.G.; Price, O.H.; Regan, A.K. Burden, effectiveness and safety of influenza vaccines in elderly, paediatric and pregnant populations. Ther. Adv. Vaccines Immunother. 2019, 7, 1–16. [Google Scholar] [CrossRef]
- Goodwin, K.; Viboud, C.; Simonsen, L. Antibody response to influenza vaccination in the elderly: A quantitative review. Vaccine 2006, 24, 1159–1169. [Google Scholar] [CrossRef]
- Ferdinands, J.M.; Fry, A.M.; Reynolds, S.; Petrie, J.G.; Flannery, B.; Jackson, M.L.; Belongia, E.A. Intraseason waning of influenza vaccine protection: Evidence from the US Influenza Vaccine Effectiveness Network, 2011–2012 through 2014–2015. Clin. Infect. Dis. 2017, 64, 544–550. [Google Scholar] [PubMed] [Green Version]
- Ray, G.T.; Lewis, N.; Klein, N.P.; Daley, M.F.; Wang, S.V.; Kulldorff, M.; Fireman, B. Intraseason waning of influenza vaccine effectiveness. Clin. Infect. Dis. 2019, 68, 1623–1630. [Google Scholar] [CrossRef] [PubMed]
- Puig-Barberà, J.; Mira-Iglesias, A.; Tortajada-Girbés, M.; López-Labrador, F.X.; Librero-López, J.; Díez-Domingo, J.; Carballido-Fernández, M.; Carratalá-Munuera, C.; Correcher-Medina, P.; Gil-Guillén, V.; et al. Waning protection of influenza vaccination during four influenza seasons, 2011/2012 to 2014/2015. Vaccine 2017, 35, 5799–5807. [Google Scholar] [CrossRef] [PubMed]
- McLean, H.Q.; Thompson, M.G.; Sundaram, M.E.; Meece, J.K.; McClure, D.L.; Friedrich, T.C.; Belongia, E.A. Impact of repeated vaccination on vaccine effectiveness against influenza A(H3N2) and B during 8 seasons. Clin. Infect. Dis. 2014, 59, 1375–1385. [Google Scholar] [CrossRef] [Green Version]
- Kwong, J.C.; Chung, H.; Jung, J.K.H.; Buchan, S.A.; Campigotto, A.; Campitelli, M.A.; Crowcroft, N.S.; Gubbay, J.B.; Karnauchow, T.; Katz, K.; et al. The impact of repeated vaccination using 10-year vaccination history on protection against influenza in older adults: A test-negative design study across the 2010/11 to 2015/16 influenza seasons in Ontario, Canada. Eurosurveillance 2020, 25, 1900245. [Google Scholar] [CrossRef] [Green Version]
- Belongia, E.A.; Skowronski, D.M.; McLean, H.Q.; Chambers, C.; Sundaram, M.E.; De Serres, G. Repeated annual influenza vaccination and vaccine effectiveness: Review of evidence. Expert Rev. Vaccine 2017, 16, 723–736. [Google Scholar] [CrossRef] [Green Version]
- Khurana, S.; Hahn, M.; Coyle, E.M.; King, L.R.; Lin, T.L.; Treanor, J.; Sant, A.; Golding, H. Repeat vaccination reduces antibody affinity maturation across different influenza vaccine platforms in humans. Nat. Commun. 2019, 10, 3338. [Google Scholar] [CrossRef] [Green Version]
- Mosterín Höpping, A.; McElhaney, J.; Fonville, J.M.; Powers, D.C.; Beyer, W.E.; Smith, D.J. The confounded effects of age and exposure history in response to influenza vaccination. Vaccine 2016, 34, 540–546. [Google Scholar] [CrossRef]
- Lu, P.J.; Hung, M.C.; O’Halloran, A.C.; Ding, H.; Srivastav, A.; Williams, W.W.; Singleton, J.A. Seasonal influenza vaccination coverage trends among adult populations, U.S., 2010–2016. Am. J. Prev. Med. 2019, 57, 458–469. [Google Scholar] [CrossRef]
- Nunes, B.; Machado, A.; Guiomar, R.; Pechirra, P.; Conde, P.; Cristovão, P.; Falcão, I. Estimates of 2012/13 influenza vaccine effectiveness using the case test-negative control design with different influenza negative control groups. Vaccine. 2014, 32, 4443–4449. [Google Scholar] [CrossRef]
- Sundaram, M.E.; McClure, D.L.; VanWormer, J.J.; Friedrich, T.C.; Meece, J.K.; Belongia, E.A. Influenza vaccination is not associated with detection of noninfluenza respiratory viruses in seasonal studies of influenza vaccine effectiveness. Clin. Infect. Dis. 2013, 57, 789–793. [Google Scholar] [CrossRef] [PubMed]
- Nickbakhsh, S.; Mair, C.; Matthews, L.; Reeve, R.; Johnson, P.C.D.; Thorburn, F.; von Wissmann, B.; Reynolds, A.; McMenamin, J.; Gunson, R.N.; et al. Virus-virus interactions impact the population dynamics of influenza and the common cold. Proc. Natl. Acad. Sci. USA 2019, 116, 27142–27150. [Google Scholar] [CrossRef] [PubMed] [Green Version]
- McElhaney, J.E.; Verschoor, C.P.; Andrew, M.K.; Haynes, L.; Kuchel, G.A.; Pawelec, G. The immune response to influenza in older humans: Beyond immune senescence. Immun. Ageing 2020, 17, 10. [Google Scholar] [CrossRef] [PubMed]
- Ng, T.W.Y.; Cowling, B.J.; Gao, H.; Thompson, M.G. Comparative immunogenicity of enhanced seasonal influenza vaccines in older adults: A systematic review and meta-analysis. J. Infect. Dis. 2019, 219, 1525–1535. [Google Scholar] [CrossRef]
- Izurieta, H.S.; Thadani, N.; Shay, D.K.; Lu, Y.; Maurer, A.; Foppa, I.M.; Franks, R.; Pratt, D.; Forshee, R.A.; MaCurdy, T.; et al. Comparative effectiveness of high-dose versus standard-dose influenza vaccines in US residents aged 65 years and older from 2012 to 2013 using Medicare data: A retrospective cohort analysis. Lancet Infect. Dis. 2015, 15, 293–300. [Google Scholar] [CrossRef] [Green Version]
- Young-Xu, Y.; Van Aalst, R.; Mahmud, S.M.; Rothman, K.J.; Snider, J.T.; Westreich, D.; Mor, V.; Gravenstein, S.; Lee, J.K.H.; Thommes, E.W.; et al. Relative vaccine effectiveness of high-dose versus standard-dose influenza vaccines among Veterans Health Administration patients. J. Infect. Dis. 2018, 217, 1718–1727. [Google Scholar] [CrossRef]
- Whitaker, J.A.; von Itzstein, M.S.; Poland, G.A. Strategies to maximize influenza vaccine impact in older adults. Vaccine 2018, 36, 5940–5948. [Google Scholar] [CrossRef]
Overall | 2016–2017 | 2017–2018 | 2018–2019 | 2019–2020 | |
---|---|---|---|---|---|
Characteristic | N (%) | N (%) | N (%) | N (%) | N (%) |
Gender | |||||
Male | 2360 (33.17) | 225 (28.96) | 551 (32.58) | 865 (36.12) | 719 (31.94) |
Female | 4754 (66.83) | 552 (71.04) | 1140 (67.42) | 1530 (63.88) | 1532 (68.06) |
Age | |||||
18–49 years | 3573 (50.22) | 471 (60.62) | 828 (48.97) | 1058 (44.18) | 1216 (54.02) |
50–64 years | 2230 (31.35) | 249 (32.05) | 566 (33.47) | 706 (29.48) | 709 (31.5) |
≥65 years | 1311 (18.43) | 57 (7.34) | 297 (17.56) | 631 (26.35) | 326 (14.48) |
Month of illness | |||||
November | 231 (3.25) | 14 (1.8) | 53 (3.13) | 0 (0) | 164 (7.29) |
December | 975 (13.71) | 120 (15.44) | 246 (14.55) | 272 (11.36) | 337 (14.97) |
January | 1925 (27.06) | 170 (21.88) | 544 (32.17) | 587 (24.51) | 624 (27.72) |
February | 2009 (28.24) | 220 (28.31) | 484 (28.62) | 721 (30.1) | 584 (25.94) |
March | 1575 (22.14) | 174 (22.39) | 247 (14.61) | 612 (25.55) | 542 (24.08) |
April | 399 (5.61) | 79 (10.17) | 117 (6.92) | 203 (8.48) | 0 (0) |
Geographic region a | |||||
Region 1 | 23 (0.32) | 2 (0.26) | 2 (0.12) | 2 (0.08) | 17 (0.76) |
Region 2 | 479 (6.73) | 90 (11.58) | 182 (10.76) | 115 (4.8) | 92 (4.09) |
Region 3 | 489 (6.87) | 87 (11.2) | 177 (10.47) | 59 (2.46) | 166 (7.37) |
Region 4 | 931 (13.09) | 129 (16.6) | 302 (17.86) | 236 (9.85) | 264 (11.73) |
Region 5 | 996 (14) | 18 (2.32) | 363 (21.47) | 264 (11.02) | 351 (15.59) |
Region 6 | 2554 (35.9) | 167 (21.49) | 305 (18.04) | 1389 (58) | 693 (30.79) |
Region 7 | 246 (3.46) | 54 (6.95) | 57 (3.37) | 29 (1.21) | 106 (4.71) |
Region 8 | 682 (9.59) | 90 (11.58) | 172 (10.17) | 157 (6.56) | 263 (11.68) |
Region 9 | 471 (6.62) | 76 (9.78) | 97 (5.74) | 66 (2.76) | 232 (10.31) |
Region 10 | 243 (3.42) | 64 (8.24) | 34 (2.01) | 78 (3.26) | 67 (2.98) |
Vaccine status | |||||
Vaccinated | 4071 (57.23) | 330 (42.47) | 841 (49.73) | 1596 (66.64) | 1304 (57.93) |
Unvaccinated | 3043 (42.77) | 447 (57.53) | 850 (50.27) | 799 (33.36) | 947 (42.07) |
Influenza | |||||
A(H1N1)pdm09 | 793 (11.15) | 4 (0.51) | 99 (5.85) | 185 (7.72) | 505 (22.43) |
A(H3N2) | 909 (12.78) | 264 (33.98) | 419 (24.78) | 208 (8.68) | 18 (0.8) |
A/not subtyped | 248 (3.49) | 0 (0) | 0 (0) | 242 (10.1) | 6 (0.27) |
B | 590 (8.29) | 78 (10.04) | 257 (15.2) | 18 (0.75) | 237 (10.53) |
Dual influenza | 3 (0.04) | 0 (0) | 3 (0.18) | 0 (0) | 0 (0) |
Non-influenza | 4571 (64.25) | 431 (55.47) | 913 (53.99) | 1742 (72.73) | 1485 (65.97) |
Unvaccinated | Vaccinated | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Control Groups | Control Groups | |||||||||||||
Influenza | Non-Influenza | Influenza | Non-Influenza | |||||||||||
Test-Negative | Virus Positive | Pan-Negative | Test-Negative | Virus Positive | Pan-Negative | |||||||||
Case | Control | Case (%) | Control | Case (%) | Control | Case (%) | Case | Control | Case (%) | Control | Case (%) | Control | Case (%) | |
18–49 years | ||||||||||||||
Influenza A(H1N1)pdm09 | 227 | 1068 | 17.53 | 297 | 43.32 | 771 | 22.75 | 184 | 1189 | 13.40 | 363 | 33.64 | 826 | 18.22 |
Influenza A(H3N2) | 292 | 1068 | 21.47 | 297 | 49.58 | 771 | 27.47 | 169 | 1189 | 12.44 | 363 | 31.77 | 826 | 16.98 |
Influenza B | 217 | 1068 | 16.89 | 297 | 42.22 | 771 | 21.96 | 111 | 1189 | 8.54 | 363 | 23.42 | 826 | 11.85 |
Any influenza a | 794 | 1068 | 42.64 | 297 | 72.78 | 771 | 50.73 | 522 | 1189 | 30.51 | 363 | 58.98 | 826 | 38.72 |
50–64 years | ||||||||||||||
Influenza A(H1N1)pdm09 | 160 | 473 | 25.28 | 148 | 51.95 | 325 | 32.99 | 153 | 863 | 15.06 | 232 | 39.74 | 631 | 19.52 |
Influenza A(H3N2) | 148 | 473 | 23.83 | 148 | 50.00 | 325 | 31.29 | 158 | 863 | 15.48 | 232 | 40.51 | 631 | 20.03 |
Influenza B | 122 | 473 | 20.50 | 148 | 45.19 | 325 | 27.29 | 85 | 863 | 8.97 | 232 | 26.81 | 631 | 11.87 |
Any influenza a | 450 | 473 | 48.75 | 148 | 75.25 | 325 | 58.06 | 444 | 863 | 33.97 | 232 | 65.68 | 631 | 41.30 |
≥65 years | ||||||||||||||
Influenza A(H1N1)pdm09 | 19 | 171 | 10.00 | 38 | 33.33 | 133 | 12.50 | 50 | 807 | 5.83 | 172 | 22.52 | 635 | 7.30 |
Influenza A(H3N2) | 35 | 171 | 16.99 | 38 | 47.95 | 133 | 20.83 | 107 | 807 | 11.71 | 172 | 38.35 | 635 | 14.42 |
Influenza B | 21 | 171 | 10.94 | 38 | 35.59 | 133 | 13.64 | 34 | 807 | 4.04 | 172 | 16.50 | 635 | 5.08 |
Any influenza a | 87 | 171 | 33.72 | 38 | 69.60 | 133 | 39.55 | 246 | 807 | 23.36 | 172 | 58.85 | 635 | 27.92 |
≥18 years | ||||||||||||||
Influenza A(H1N1)pdm09 | 406 | 1712 | 19.17 | 483 | 45.67 | 1229 | 24.83 | 387 | 2859 | 11.92 | 767 | 33.54 | 2092 | 15.61 |
Influenza A(H3N2) | 475 | 1712 | 21.72 | 483 | 49.58 | 1229 | 27.88 | 434 | 2859 | 13.18 | 767 | 36.14 | 2092 | 17.18 |
Influenza B | 360 | 1712 | 17.37 | 483 | 42.70 | 1229 | 22.66 | 230 | 2859 | 7.45 | 767 | 23.07 | 2092 | 9.91 |
Any influenza a | 1331 | 1712 | 43.74 | 483 | 73.37 | 1229 | 51.99 | 1212 | 2859 | 29.77 | 767 | 61.24 | 2092 | 36.68 |
Controls | ||||||
---|---|---|---|---|---|---|
Influenza Test-Negative | Non-Influenza Virus Positive | Pan-Negative | ||||
VE (%) a | 95% CI (%) | VE (%) a | 95% CI (%) | VE (%) a | 95% CI (%) | |
18–49 years | ||||||
Influenza A(H1N1)pdm09 | 41 | 25–53 | 52 | 36–64 | 35 | 16–49 |
Influenza A(H3N2) | 42 | 26–54 | 51 | 34–64 | 36 | 18–50 |
Influenza B | 55 | 41–65 | 62 | 48–72 | 51 | 35–63 |
Any influenza b | 44 | 35–52 | 53 | 42–62 | 39 | 28–48 |
50–64 years | ||||||
Influenza A(H1N1)pdm09 | 53 | 38–65 | 47 | 24–62 | 57 | 41–68 |
Influenza A(H3N2) | 26 | 1–45 | 13 | −30–41 | 26 | −1–46 |
Influenza B | 56 | 38–68 | 52 | 29–68 | 57 | 39–70 |
Any influenza b | 41 | 29–51 | 36 | 16–51 | 43 | 30–53 |
≥65 years | ||||||
Influenza A(H1N1)pdm09 | 34 | −29–66 | 41 | −26–73 | 27 | −46–63 |
Influenza A(H3N2) | 6 | −60–45 | 15 | −82–60 | −4 | −84–41 |
Influenza B | 60 | 19–80 | 65 | 18–85 | 55 | 6–78 |
Any influenza b | 28 | 0–49 | 40 | 0–64 | 24 | −8–47 |
≥18 years | ||||||
Influenza A(H1N1)pdm09 | 46 | 36–55 | 50 | 38–59 | 45 | 33–54 |
Influenza A(H3N2) | 32 | 19–42 | 35 | 19–48 | 28 | 14–40 |
Influenza B | 54 | 44–62 | 57 | 46–66 | 52 | 41–61 |
Any influenza b | 40 | 33–46 | 44 | 35–52 | 38 | 30–45 |
Non-Influenza Virus Positive Controls | Pan-Negative Controls | p-Value | |||
---|---|---|---|---|---|
Total | Vaccinated (%) | Total | Vaccinated (%) | ||
18–49 years | 660 | 363 (55.0) | 1597 | 826 (51.7) | 0.012 |
50–64 years | 380 | 232 (61.1) | 956 | 631 (66.0) | 0.198 |
≥65 years | 210 | 172 (81.9) | 768 | 635 (82.7) | 0.709 |
≥18 years | 1250 | 767 (61.4) | 3321 | 2092 (63.0) | 0.245 |
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Hu, W.; Sjoberg, P.A.; DeMarcus, L.S.; Robbins, A.S. Influenza Vaccine Effectiveness Estimates among US Department of Defense Adult Beneficiaries over Four Consecutive Influenza Seasons: A Test-Negative Design Study with Different Control Groups. Vaccines 2022, 10, 58. https://doi.org/10.3390/vaccines10010058
Hu W, Sjoberg PA, DeMarcus LS, Robbins AS. Influenza Vaccine Effectiveness Estimates among US Department of Defense Adult Beneficiaries over Four Consecutive Influenza Seasons: A Test-Negative Design Study with Different Control Groups. Vaccines. 2022; 10(1):58. https://doi.org/10.3390/vaccines10010058
Chicago/Turabian StyleHu, Wenping, Paul A. Sjoberg, Laurie S. DeMarcus, and Anthony S. Robbins. 2022. "Influenza Vaccine Effectiveness Estimates among US Department of Defense Adult Beneficiaries over Four Consecutive Influenza Seasons: A Test-Negative Design Study with Different Control Groups" Vaccines 10, no. 1: 58. https://doi.org/10.3390/vaccines10010058
APA StyleHu, W., Sjoberg, P. A., DeMarcus, L. S., & Robbins, A. S. (2022). Influenza Vaccine Effectiveness Estimates among US Department of Defense Adult Beneficiaries over Four Consecutive Influenza Seasons: A Test-Negative Design Study with Different Control Groups. Vaccines, 10(1), 58. https://doi.org/10.3390/vaccines10010058