Research and analysis

Laboratory reports of hepatitis A infections in England and Wales: January to March 2021

Published 23 January 2024

Applies to England and Wales

A total of 106 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 first quarter of 2021 (January to March 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 66% increase on the reports in the fourth quarter of 2020 (n=64), (figure 2).

Of the 106 lab-confirmed new cases, 91 were reported through SGSS, after excluding corrections and before including an additional 15 confirmed cases identified by VRD (figure 1).

Table 1. Laboratory reports of hepatitis A in England and Wales, January to March 2021

Age group Females Males Total
Less than 1 year 0 0 0
1 to 4 years 1 1 2
5 to 9 years 2 6 8
10 to 14 years 3 2 5
15 to 24 years 8 3 11
25 to 34 years 5 8 13
35 to 44 years 4 3 7
45 to 54 years 3 5 8
55 to 64 years 16 8 24
65 years and over 14 14 28
Total 56 50 106

Note: Since Q1 2020, these reports have presented the number of cases excluding false positives and including additional cases identified by the 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 UKHSA region accounted for 22% (n=23) of reports, followed by 16% (n=17) from the South West region. Age group and sex were well reported (no missing values table 1). There were 28 (26%) reports among those aged over 65, followed by 24 (23%) in the 55 to 64 years age group and 13 (12%) in those aged 25 to 34 years. Females accounted for 53% of reports (n=56) and males for 47% (n=50).

The following flowchart shows there were 134 reports of new patients with hepatitis A reported through SGSS. There were 3 corrections (laboratories informing VRD that reports had been false positives) leaving 131 laboratory reports of new patients through SGSS. Samples from 96 patients were sent to VRD for confirmation and 40 cases were not confirmed. After excluding non-confirmed cases, 91 cases remained. Fifteen cases were confirmed in VRD, but not reported through SGSS, giving a total of 106 new cases identified through SGSS or VRD in Q1 2021.

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

Figure 2. Laboratory reports of hepatitis A by age and sex in England and Wales, January 2007 to March 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 91 patients notified as having acute hepatitis A virus (HAV) infection during the first quarter of 2021, 58 had samples forwarded to the Virus Reference Department for genotyping. In addition, 15 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 70 patient samples could be genotyped over this period: 11 were genotype IA (16%), 49 were genotype IB (70%) and 10 were genotype genotype IIIA (14%).

Of these samples, 12 were associated with travel (17%), 57 had no travel history (81%) and one had no information (1%).

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 January to March 2021 (n=70)