hepatitis A outbreaks in US/vaccination

​The CDC just had yet another advisory. This time on outbreaks of hepatitis A in multiple states (see https://emergency.cdc.gov/han/han00412.asp ).

Details:

--from Jan 2017 to April 2018, there were >2,500 reports of hepatitis A virus (HAV) infections associated with person-to-person transmission in several states in the US

--for >1900 of them, risk factors were known: >1300 (68%) reported drug use (injection on non-injection), homelessness or both.

--in the 1980's, drug use was a risk factor in >20% of HAV infections per the CDC, but no large outbreaks since adoption of vaccine recommendations in 1996

--from the recent outbreaks:

    --California 2018: 704 cases, 461 hospitalizations, 21 deaths: majority homeless or using illicit drugs in setting of limited sanitation

    --Kentucky 2017-18: 445 cases, 6 deaths: 3% homeless, 68% illicity drug use, 17% both, <1% MSM, 21% no known risk factors

    ​--Michigan 2016-18: 840 cases, 677 hospitalized, 27 deaths: 50% illicit drug users, 14% homeless, 40% neither homeless nor illicit drug users, 15% MSM, 8% incarcerated, 5% food workers

    --Utah 2017-18: 253 cases: 37% homeless and drug use, 23% drug use, 7% homeless, 15% incarcerated

Recommendations:

--at risk people: drug use, homelessness, MSM, recent incarceration

--vaccinate those in jails; syringe service programs; substance abuse treatment programs; and at-risk people in EDs, homeless shelters/warming centers, food distribution centers, venues where high risk people seek care

--educate people who are at risk through targeted media campaigns

--vaccinate people traveling to or working in countries that have high or intermediate endemicity of HAV

--also, vaccinate those with occupational risk factors for HAV infection, chronic liver disease, clotting-factor disorders, household members/contacts of those arriving from countries with high or intermediate HAV endemicity; and those who have contact with persons with HAV

--and, any person wishing to obtain immunity

--if someone is exposed to HAV: give one dose of single-antigen HAV vaccine or immune globulin as soon as possible and within 2 weeks of exposure

Commentary:

--hepatitis A infection often has significant morbidity and some mortality (especially when there is infection on top of another hepatitis), as noted above

--the general recommendations for kids is to immunize all of them with 2 doses at age 12 months (see https://www.cdc.gov/vaccines/schedules/downloads/child/0-18yrs-combined-schedule-bw.pdf )

--though these outbreaks were mostly in people who were homeless etc, there have been some outbreaks in those consuming contaminated vegetables (eg the 2003 outbreak involving 601 patients in a restaurant in Pennsylvania from eating green onions: see Wheeler C. N Engl J Med 2005; 353: 890), contaminated shellfish, etc

--and, given the current political climate and devastation of regulations that protect us (at least somewhat), I am even more concerned about more infections/toxins making their way into our foods through lax monitoring of foods and the environment. And foods grown in other countries (as apparently the green onions were in the above outbreak) may be even less monitored for safety. it is quite striking the number of food recalls by the government (see https://www.foodsafety.gov/recalls/recent​ , which lists 24 in the past couple of months from US food products), many of which note "without benefit of federal inspection".  and this could get a lot worse, with some of these foods causing pretty devastating diseases...

--an additional concern is that many of our patients and staff travel to countries where hepatitis A in endemic (ie, most of the world), so the chances of their getting hepatitis A while there, or bringing it back here and spreading it, is potentially significant (and the average incubation period is 28 days, illness can occur up to 50 days after exposure, and an HAV-infected person can be viremic for up to 6 weeks through their clinical course and excrete virus in stool 2 weeks before being symptomatic: ie, there may be many asymptomatic carriers lurking around). And some people are asymptomatic (especially in young people: 70% of those <6 yo are asymptomatic)

So, all in all, I personally think that everyone should be immune to HAV (not just targeted groups). For those coming from endemic regions, I usually check an HAV IgG antibody (since about 70-90% are immune) and immunize those nonimmune. others just get the shots.

The above data do suggest this approach is reasonable (vaccination is already routinely given to kids, the infection can be really bad, a reasonably large number of infected people have "no known risk factors", there is more travel to/from higher risk countries by people and by foods, and vaccination works...). and the CDC even has their last recommendation to vaccinate "any person wishing to obtain immunity".