Hepatitis A

Question 1

Incubation period of Hep A

Answer 1

28 days, with a range of 15–50 days.

Question 2

Infectious period of Hep A

Answer 2

2 weeks before to one week after onset of symptoms/Jaundice/dark urine

Question 3

Clinical syndrome of hep A

Answer 3

90% of young children asymptomatic
70-90% of adults symptomatic

Abrupt onset fever, RUQ pain, jaundice.

Lasts weeks but can relapse for months

Question 4

Hep A IgM - when does it become detectable and how long does it last?

Answer 4

Should be positive within 5 days of symptoms (according to SMI)
Can persist for 3-6 months (usually 45-60 days)

Question 5

Hepatitis A - duration of detectable virus in blood and stool?

Answer 5

Hepatitis A virus is excreted in the bile and shed in the stools of infected persons. Peak excretion occurs during the 2 weeks before onset of jaundice; the concentration of virus in the stools drops after jaundice appears but may persist for more than 40 days. Children may excrete the virus for longer (months) than adults, although a chronic persistent state does not exist.

Question 6

Hep A vaccine
- What type of vaccine?
- Who is given it?
- What is the schedule?

Answer 6

Purified, inactivated virus grown in human diploid cells
Given
- post exposure
- at risk groups (occupational, MSM, PWID, people who receive blood products (haemophilliacs))
- outbreak management
Schedule
- Two doses 6-12 months apart provides a min of 25 years immunity
- one dose (as given in outbreak) of monovalent hepatitis A vaccine provides protection for up to 12 months. However, for long term protection a second dose of hepatitis A vaccine should be given at 6 to 12 months after the initial dose. This second dose results in a substantial increase in the antibody titre and will give immunity for at least 25 years.

Question 7

Hepatitis A post exposure prophylaxis up to day 14
- Who gets it?
- If getting something what?

Answer 7

Close contacts
- a person living in the same household as the index case or regularly sharing food or toilet facilities
- if the index case is a child in nappies or requiring assistance with toileting, any person who has been involved in nappy changing or assistance with toileting, including nursery school staff and childminders during the infectious period
- individuals injecting drugs and sharing injecting paraphernalia with the index case

PEP
- >60 or chronic liver disease/immunocomp = vaccine + HNIG
- 1-60 - vaccine
- <12 months 0 =

Question 8

Hepatitis A virology? Family, baltimore, size, characteristics, transmission

Answer 8

HAV is a member of the genus Hepatovirus in the family Picornaviridae.

+ssRNA, naked

Enterically transmitted (outbreaks in PWID, MSM, homeless)