Hepatitis A infections increasing

 

The CDC reported a spike in hepatitis A infections in men who have sex with men (MSM), see https://www.cdc.gov/mmwr/volumes/70/wr/pdfs/mm7024a2-H.pdf ) 

 

Details: 

--from 1994-2011, there was a 95% decrease in hepatitis A infections from 12 cases/100K population to 0.4 cases/100K 

--from 2012-2015, the number of cases plateaued 

--from 2016-2018, the incidence increased 294% vs 2013-2015 

    --most cases occurred in high-risk people (MSM, homeless, injection and noninjection drug users)

    --from Jan 2017-Nov 2018, the CDC reported 260 cases of confirmed hep A (symptoms of viral hepatitis and positive IgM against hepatitis A virus, HAV) in MSM in 8 states (had been 16 cases from all 50 cases during 2013-2015), in California, Colorado, Georgia, Maryland, New York, North Carolina, Pennsylvania and Virginia. These states reported 1,229 additional cases without indication of MSM status 

 

--median age 32, symptoms were mostly malaise (89%), dark urine (85%), jaundice (81%) 

--during incubation period (presymptomatic, but transmissible virus): international travel in 21%, and 24% reported injection or noninjection drug use. 

--8% reported at least one dose of hep A vaccine (standard is 2 doses 6-12 months apart) 

--95% of those who had further testing (126 of 133) had genotype 1A, 43% of them infected with identical strains and were genetically identical to one of 3 strains found in a recent HAV outbreak in MSM in three European Union (further suggesting high transmissibility from few sources) 

--124 of the 260 cases (48%) were hospitalized for median of 3 days. No deaths 

   --additional cases of hep A were reported in California, Kentucky, Michigan and Utah in those using drugs or homeless 

 

Commentary: 

--this increase in a vaccine-preventable infection by HAV is quite concerning, and raises (again) the very reasonable argument (to me) that hepatitis A immunity should be ensured for the whole US population (kids already do get it as part of their routine immunizations), for the following reasons: 

    --hepatitis A is a vaccine-preventable disease 

    --hepatitis A is a major cause of acute hepatitis worldwide

    --the disease often has high morbidity (people feel miserable, and the attendant fatigue, for example, can last for weeks) 

    --some patients have much more serious infections, including fulminant hepatitis, especially if they have underlying chronic hepatic inflammation (including the rather large US population who have non-alcoholic liver disease, which is remarkably common in the US population, given our large numbers of people with obesity, diabetes, prediabetes, etc): see a 3-part series of blogs on NAFLD: http://gmodestmedblogs.blogspot.com/2016/08/there-have-been-several-articles.html , http://gmodestmedblogs.blogspot.com/2016/08/non-alcoholic-fatty-liver-disease-2.html , http://gmodestmedblogs.blogspot.com/2016/08/non-alcoholic-fatty-liver-disease-3.html; and for others: http://gmodestmedblogs.blogspot.com/search?q=nafld

    -- for the 2020 CDC recommendations, see https://www.cdc.gov/mmwr/volumes/69/rr/rr6905a1.htm, which include vaccinating "persons with chronic liver disease, including but not limited to persons with hepatitis B virus (HBV) infection, hepatitis C virus (HCV) infection, cirrhosis, fatty liver disease, alcoholic liver disease, autoimmune hepatitis, or an alanine aminotransferase (ALT) or aspartate aminotransferase (AST) level persistently greater than twice the upper limit of normal"

        -- for a review of the medical literature on the dangers of acute hepatitis infection on top of chronic liver disease: see https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7504211/

    --there is more and more international travel (prior to covid, at least), leading to more potential contact with the hepatitis A virus, which is easily transmitted, largely from fecal-oral route (it was notable in the above CDC report that 21% of those infected had international travel with infectious but presymptomatic hepatitis A, posing a clear risk to others) 

        --and, people coming from higher prevalence countries who are not immune have a high likelihood of visiting their countries and potentially getting infected 

    -- several sexual acts also do lead to increased potential for fecal-oral transmission 

    -- it is more likely that a universal vaccination policy will reach more people than the targeted approach to high-risk individuals that the Advisory Committee on Immunization Practices (ACIP) recommended in 1996. A routinized vaccination scheduled is more easily implemented in clinical practice than one that requires more clinician involvement (how many of us routinely think about hep A when seeing a patient with likely NAFLD??). and the vaccination rates have been low  with the ACIP targeted approach

 

-- as a perspective, the guidelines recommend tetanus boosters every 10 years, which undoubtedly is negligibly followed, yet there are almost no cases of tetanus in the US (in 2017 there were 33 cases and 2 deaths, in 2018 and 2019 there were zero reported cases). though the CDC does offer the potential for Tdap vaccines every 10 years, pertussis immunity lasts only a couple of years (see https://www.cdc.gov/pertussis/about/faqs.html ). the reason i mention this is that pretty marginal adult vaccines (eg Td, though Tdap has a bit better logic to it) are approved, yet HAV vaccine is not (other than in kids)??? for more on the increasing pertussis outbreaks, see http://gmodestmedblogs.blogspot.com/2018/10/pertussis-epidemics-increasing.html .

--for a pretty recent blog on hepatitis A outbreaks in the US, see http://gmodestmedblogs.blogspot.com/2019/06/increasing-measles-and-hepatitis.html 

 

Limitations 

--not a lot of granular data presented in this report: eg, no data on coinfection with HIV or other commorbidites, immunocompromising medical conditions; and no social/economic/demographic data to understand the role of poverty, stress, diet/exercise, living conditions, etc

--data were collected in different states and not standardized across the US, especially data on sexual orientation and sexual practices were not ascertained in many states

--some people reported multiple high risk behaviors, so hard to distinguish which were the most relevant to getting HAV infection in this report 

 

So personally, I do make sure my patients are immune to HAV, often by checking a hepatitis A IgG titer for my foreign-born patients (since >90% of my patients are already immune), or just giving the vaccine to lesser exposed individuals: 2 shots, 6 months apart. There is no doubt that HAV is a highly transmissible virus with significant morbidity and some mortality, is largely preventable by a simple and low-cost vaccination, and one with likely at least as much benefit compared to some others we more routinely give

 

geoff

 

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