Increasing measles and hepatitis A outbreaks

As has hit the press over the past few months, there has been a widespread increase in measles cases in the US: 940 cases confirmed in 26 states, as of 5/24/19 (see https://www.cdc.gov/measles/cases-outbreaks.html). Of note:

--this is an increase of 60 cases over the prior week

--this is the greatest number of cases reported since 1994 (and since 2000, when measles was declared “eliminated”)

-- The states that have reported cases to CDC are Arizona, California, Colorado, Connecticut, Florida, Georgia, Illinois, Indiana, Iowa, Kentucky, Maine, Maryland, Massachusetts, Michigan, Missouri, New Mexico, Nevada, New Hampshire, New Jersey, New York, Oklahoma, Oregon, Pennsylvania, Texas, Tennessee, and Washington.  ie, the whole west coast, the south/west regions (all the way through OK and TX), the more eastern middle of the country (eg IA, MO and through to KY and TN), southeast (FL, GA) and northeast (all but VT)

--this is a dramatic increase:

    --2016: 86 cases in entire year

    --2017: 120 cases in entire year

    --2018: 372 cases in entire year

    --2019: 940 cases in less than 5 full months

--majority of cases were in people who were not vaccinated

--measles is common in much of the world (hence, with our increasingly mobile population, we need to be vaccinated to avoid imported cases)

--and much of the problem stems from vocal popular misinformation (?fake news) about associations between MMR vaccines and autism, etc; as well as resistance in some religious communities (eg Orthodox Jews). And there is a large outbreak in Israel

--before 1963 (when the first vaccine became available), nearly all children got measles, with 3-4 million people infected annually in the US, 400-500 people dying, 48,000 hospitalized, 1,000 getting encephalitis

    -- (from a newer CDC site): about 1 in 4 who get measles will be hospitalized, 1 in 1000 get encephalitis, and 1-2 in 1000 die independent of high quality medical care [not sure why these numbers are different; perhaps these are cases of more severe measles, since many kids in the past had pretty mild cases]

--measles is one of the most contagious infections we know: see http://gmodestmedblogs.blogspot.com/2017/11/herd-immunity-epidemics-and.html , which argues that there needs to be a whopping 92-95% of the population having measles immunity to achieve effective "herd immunity" (ie, unless 92-95% are immune, now mostly by vaccination since overt disease is still pretty rare, the virus can spread in the population). By contrast, flu or ebola need 50% of the community immune for herd immunity 

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The CDC also published a report on the increasing number of hepatitis A infections in the United States between 2013-2018 (see https://www.cdc.gov/mmwr/volumes/68/wr/mm6818a2.htm?s_cid=mm6818a2_w)

Details:

-- from 2016-2018, there was a 294% increase in cases, as compared to 2013-2015, related to outbreaks associated with contaminated food, among men who have sex with men, and, primarily, among persons who report drug use or are homeless

-- during 2016-2018, the CDC received approximately 15,000 reports of hepatitis A infections in the US

-- in 2017 the vast majority of these reports related to multiple outbreaks of hepatitis A were in those who were reporting drug use or were homeless

-- 9 states had increases of greater than 500% increase during this time period: Missouri, Arkansas, Tennessee, Kentucky, Indiana, Ohio, West Virginia, Utah, Hawaii. Also Washington DC

-- 8 states had a 100-500% increases: California, Florida, Louisiana, Massachusetts, Michigan, South Carolina, Virginia, and Wyoming.

-- molecular epidemiology has found that there has been a shift of genotypes away from the dominant genotype 1A found historically in North and South America

Commentary:

-- as a perspective, rates of hepatitis A had declined by 95% during 1996-2011

will append my recent blog on hepatitis A from 6/13/18 (see http://gmodestmedblogs.blogspot.com/2018/06/hepatitis-outbreaks-in-usvaccination.html  ):

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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 is 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".

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So, regarding measles and hepatitis A vaccines:

--as should be evident: vaccinations work (though some better than others).   

   --especially the older, tried-and-true ones (some of the newer ones do have unsuspected adverse effects, eg the old Lyme disease one, or the older rotavirus one

--one of the downsides of the rapid access to all kinds of unfiltered news is the proliferation of anti-science (climate change) and anti-medicine (also, theoretically, part of science…) news

--and there may be significant under-reporting of cases, especially of measles where most clinicians (esp those under 60-70 yo) have never seen it…

--it is really important that we clinicians and our public health systems are aggressive in promoting these really important vaccines; the above outbreaks truly represent massive public health failures....

geoff

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