Volume 27, Number 6—June 2021
Research Letter
Changing Molecular Epidemiology of Hepatitis A Virus Infection, United States, 1996–2019
, Guo-Liang Xia, Zoya Dimitrova, Yulin Lin, Martha Montgomery, Ryan Augustine, Saleem Kamili, and Yury Khudyakov
Table
Genotype distribution of HAV specimens collected through surveillance programs and outbreak investigations, United States, 1996–2019*
| Year | No. (%) HAV surveillance specimens † |
No. (%) HAV outbreak specimens‡ |
No. (%) HAV specimens |
|||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Total | IA | IB | IIIA | Total | IA | IB | IIIA | Total | IA | IB | IIIA | |||
| 1996–2015 |
1,706 |
1,587 (93.0) |
110 (6.4) |
9 (0.5) |
836 |
706 (84.4) |
127 (15.2) |
3 (0.4) |
2,542 |
2,293 (90.2) |
237 (9.3) |
12 (0.5) |
||
| 2016–2019 | ND |
6,661 | 1,046 (15.7) | 5,518 (82.8) | 97 (1.5) | 6,661 | 1,046 (15.7) | 5,518 (82.8) | 97 (1.5) | |||||
*Since 2014, the United States has not had established HAV surveillance programs in place to provide specimens for molecular testing of surveillance cases. Specimens collected as part of outbreak investigations during 2016–2019, might include some sporadic cases. During 1996–2015, ≈130 HAV specimens/year were tested; During 2016–2019, 1,660 specimens/year were tested. HAV, hepatitis A virus; ND, no data. †Surveillance specimens tested by the Centers for Disease Control and Prevention (CDC) during 1996–2013 included sentinel county surveillance (n = 1,234) during 1996–2006; the Emerging Infectious Disease Program (n = 418) during 2007–2013; and the Border Infectious Disease Surveillance (n = 54) system during 2007–2013. ‡Outbreak specimens sequenced during 1996–2015 (n = 836) were tested by CDC. Outbreak specimens sequenced during 2016–2019 (n = 6,661) included data from CDC testing (n = 5,068) and data captured through technical assistance offered to sites, which included data from Sanger sequences reported to CDC for technical assistance and analysis from state and local public health laboratories (n = 341) and the Food and Drug Administration (n = 3); data from ultradeep sequencing and submission to the Global Hepatitis Outbreak and Surveillance Technology portal by state and local public health laboratories (n = 1,249).