[ed. note: Michael Jorrin, who I dubbed “Doc Gumshoe” years ago, writes for us a couple times a month on medicine and health issues. He is not a physician, but explains the science and the data well, and helps provide some background understanding and perspective that often benefits both investors and folks who are attentive to their own health. He chooses his own topics and doesn’t usually focus on investment ideas, but follows our trading rules when investments are featured in his articles. You can see his past articles and comments here.]
It’s always the scary news that hits prime time and social media news feeds and the front pages of even reputable papers like the Good Gray New York Times, as it used to be called before it got so trendy with giant color spreads on every page. A few days ago, the Times broke the news that in the United States 234 pregnant women had been infected with the Zika virus. A statement that, while not intended to instill panic, was by no means calm inducing. What, women infected with Zika in the United States? One had to read considerably further on in the article to learn that not one single one of those women had been infected in the United States. These unfortunate ladies were in the United States, but they had been infected outside the United States. Indeed, of the 755 confirmed cases of Zika in the US (according to the CDC), not one single one acquired the infection in the US.
It is thought, however, that during the summer months, there may be some Zika infections in Florida and along the Gulf coast, in areas where the Aedes aegypti mosquito is likely to breed. But this bug travels only a very short distance – maybe a quarter of a mile – from where it is hatched, and to transmit the infection, it first has to suck a little blood from an infected human, so there has to be an infected human near where the mosquito hatches, and since there are supposedly not many such in the whole US, the chances of transmission in the continental US, at least, may be small.
I do find the figures a mite dubious, however. If there are only 755 Zika-infected persons in the US, how can 234 of them be pregnant women? My suspicion is that it was mostly pregnant women who got tested, based on their rational fears for their unborn babies. There was no reason for symptom-free men and non-pregnant women to go and get tested, so that likely accounts for that huge disparity. But that would suggest that there are many Zika-infected people out there who have no symptoms, have not been tested, and are potential reservoirs for the virus.
But let’s turn our attention away from the headline-grabbing Zika virus and consider the enormous progress that has been made in the treatment of another virus, much more threatening to us, and take a look at a prospective treatment that promises to hugely to reduce the time it takes to achieve a cure. That virus is hepatitis C.
What is hepatitis C and why is it of particular concern?
Hepatitis C, by any measure, is a highly successful virus, by which I mean that it has all the characteristics that lead to widespread transmission. It is transmitted by blood (more about that later); in the early stages of infection it is almost always asymptomatic, meaning that infected persons have no notion that they have been infected and have no reason to seek treatment. But most patients, perhaps as many as 85%, go on to develop a chronic infection. Again, most of these chronic hep C patients have only mild symptoms such as fatigue. However, about 20% will eventually develop cirrhosis, and some of these will experience liver failure. Hep C is the most frequent indication for liver transplantation in the US, and was listed as the cause of death on 19,659 death certificates in 2014.
The factor that enormously contributes to the transmission of hep C is that it can take a very long time for the cirrhosis signs to appear, sometimes as long as 40 years, during which time the virus is present in the patient and can be transmitted to another person.
And it is estimated that there are almost four million persons with chronic hep C in the US at this time, many of whom have no idea that they are infected. Nonetheless, these individuals can pass the virus on to another person.
How does this happen?
How is hepatitis C transmitted?
Hep C is transmitted in blood. Until the mid 1990s, blood transfusions were the source of much hep C infection, but starting in 1992 it became standard practice for all donated blood and organs to be tested for hep C, and subsequently this source of transmission was essentially halted. Indeed, the incidence of hep C plummeted after blood used in transfusions began to be tested, from a peak of about 6,000 reported new cases per year before 1992, to about 2,000 reported new cases currently. However, there is an enormous disparity between reported cases and estimated actual cases. Since most infected persons do not demonstrate symptoms, most new cases are not reported. The CDC estimates that for every reported case, about 13 more cases go unreported.
Accidental needle sticks in medical facilities may account for a few cases, and it should be assumed that most of those cases are tested and reported, and that the individuals who acquire hep C by that route are not major reservoirs of infection.
But the largest numbers of hep C infections are transmitted through intravenous drug use (IDU). Despite repeated warnings, despite programs to provide free hypodermics to reduce that risk, junkies routinely continue to share needles when they partake of their drug of choice in little social get-togethers. It’s hard to say whether they are aware of the risks they are taking. If some of their fellow-junkies are hep C infected, they may be symptom-free and thus unaware, or they may be in denial, of they may be infected with a disease even more serious than hep C, namely terminal fatalism – “It doesn’t matter – my life is a mess anyway.”
My non-medical response to this is, “Just because your life is a mess doesn’t give you the right to mess up somebody else’s life.”
An interesting and frequently overlooked route of hep C transmission is tattooing. I find no mention of tattooing as a risk factor for hep C in a lot of widely-available material, although the Mayo Clinic does mention tattooing as risk factor. Tattooing is done by injecting pigments into the dermal layer of the skin (beneath the epidermis) by means of a needle that punctures the skin at the rate of 90 to 150 times per second. If the tattooing needle is not sterilized between uses, or if the pigments used to create the tattoo are not sterile, tattooing might play the same role in transmitting infections as IDU.
Tattooing is especially prevalent among younger people, also in some socio-economic and ethnic groups, and especially in prison. In trying to determine the risk for hep C transmission presented by tattooing, it is crucial to exclude drug users and individuals who may have acquired hep C through other routes. One study, a meta-analysis of 83 studies in which the relationship between tattooing and hep C was a study variable, found a combined odd ratio of 2.24 for the link, meaning that tattooed individuals were more than twice as likely to have hep C as non-tattooed individuals, when other possible routes of transmission were excluded. In prison, that odds ratio increases to about 5. (Jafari S. Int J Infect Dis 2010;14:e928e940)
The study authors point out that tattooing has also been reported to be a strong risk factor for the transmission of several other diseases, including HIV, hepatitis B, leprosy, and methicillin resistant Staphylococcus aureus (MRSA). They also point to an association between the surface area covered by the tattoo and the risk of hep C infection. Larger tattoos, covering more than 20 cm2 (about 60 square inches) increase the odds ratio for hep C infection to more than 12.
In another study that found a strong association between tattooing and hep C, the finding was that individuals with hep C were 5.17 times more likely to have a tattoo than those without hep C. (Carney S. Hepatology 2013;57:2117-2123)
Those two analyses are not in disagreement, by the way. In the first analysis, they were comparing tattooed and non-tattooed individuals and found that those with tattoos were more than twice as likely to have hep C, while in the second analysis, they were looking at individuals with and without hep C and found that those with hep C were more than five times as likely to be tattooed.
I find it difficult to understand how a risk factor that is intuitively obvious, that affects a significant number of persons, and that results in major health-care costs – think of the cost of treating prisoners who get infected with hepatitis C – is not subjected to more prominent warnings. Is it viewed as a “life-style choice,” favored by some demographic cohorts, and therefore not subject to criticism?
But let us move on to some better news.
How is hepatitis C treated these days?
The Gumshoe citizenry surely have heard of Sovaldi and Harvoni, if for no other reason than the immense impact these two drugs have had on Gilead’s fortunes. Those two, along with another newcomer, Daklinza, have completely changed the hep C treatment landscape, and that is by no means an exaggeration.
Prior to the introduction of these agents, treatment for hep C was based on some form of interferon given with ribavirin. Interferons are cytokines, a protein that is an essential actor in the immune system and is part of the organism’s defense against viruses. The particular form of interferon that was most commonly used in patients with hep C was pegylated interferon alpha 2b, in which the interferon molecule is linked to polyethylene glycol to extend the activity of the interferon in the body and make it possible to give the interferon injections weekly rather than two or three times per week. (If polyethylene glycol sounds familiar to you, it’s because that’s what antifreeze is, and it’s also an ingredient in some cosmetics.)
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