Research and analysis

Laboratory reports of hepatitis A infections in England and Wales: April to June 2021

Published 23 January 2024

Applies to England and Wales

A total of 82 laboratory reports of new patients with hepatitis A were reported to UK Health Security Agency (UKHSA) from the Second Generation Surveillance System SGSS during the second quarter of 2021 (April to June 2021) (see table 1 and figure 1).

This total was calculated after:

  • exclusion of patients with samples sent to the Virus Reference Department (VRD) that were not confirmed as having had a recent hepatitis A virus infection (‘corrections’), as well as
  • inclusion of additional patients confirmed by VRD

This was a 23% increase on the reports in the first quarter of 2021 (n=106). A total of 73 patients were reported through the Second Generation Surveillance System (SGSS), after excluding corrections and before including an additional 9 confirmed cases identified by VRD (figure 1).

Table 1. Laboratory reports of hepatitis in England and Wales, April to June 2021

Age group Females Males Total
Less than 1 year 0 1 1
1 to 4 years 2 8 10
5 to 9 years 7 7 14
10 to 14 years 1 2 3
15 to 24 years 7 4 11
25 to 34 years 3 3 6
35 to 44 years 2 3 5
45 to 54 years 1 2 3
55 to 64 years 6 4 10
65 years and over 9 10 19
Total 38 44 82

Note: Since Q1 2020, these reports have presented the number of cases excluding false positives and including additional cases identified by VRD. Hence, numbers are not directly comparable to quarters prior to Q1 2020; it should be noted that false positives are more likely in older age groups.

The London region accounted for 29% (n=24) of reports, followed by 15% (n=12) and 13% (n=11) from East of England and West Midlands, respectively. Age group and sex were well reported (no missing values, Table 1). There were 19 (23%) reports among those aged over 65, followed by 14 (17%) reports among those in the 5 to 9 years age group. Males accounted for 54% of reports (n=44), and females 46% (n=38).

The following flowchart shows there were 126 reports of new patients with hepatitis A reported through SGSS. There were 12 corrections (laboratories informing the VRD that reports were false positives or due to reporting issues, or quality controls), leaving 114 laboratory reports of new patients through SGSS.

Samples from 84 patients were sent to VRD for confirmation and 41 cases were not confirmed. After excluding non-confirmed cases, 73 cases remained. Nine cases were confirmed in VRD but not reported through SGSS, giving a total of 82 new cases identified through SGSS or VRD in Q2 2021.

Figure 1. Flowchart of laboratory reports of hepatitis A by confirmation status (England and Wales), April to June 2021

Figure 2. Laboratory reports of hepatitis A by age and sex in England and Wales, April 2007 to June 2021

Notes:

  1. All figures are provisional and subject to change as records are updated.
  2. From Q1 2020, the central number of cases presented excludes false positives and includes additional cases identified by VRD. Hence, numbers are not directly comparable to previous quarters.
  3. It should be noted that false positives are more likely in older age groups.

Reference laboratory confirmation and phylogeny of hepatitis A infections

Of the 73 patients notified as having acute hepatitis A virus (HAV) infection during the second quarter of 2021, 45 had samples forwarded to the Virus Reference Department for genotyping. In addition, 9 patients were confirmed to have acute HAV infection that had not been reported through the laboratory reporting system although all the English cases were recorded in HPZone.

A total of 53 patient samples could be genotyped over this period: 14 were genotype IA (26%), 25 were genotype IB (47%) and 14 were genotype IIIA (64%). Of these samples, 18 were associated with travel (34%), 34 had no travel history (64%) and 1 had no information (2%).

This information is presented below as a phylogenetic tree (figure 3) where each sequence is represented by a dot followed by the patient region, and the week of sampling in brackets.

Figure 3. Phylogenetic tree of genotype IA, IB, and IIIA sequences April to June 2021 (n=53)