Why quarantine for measles is critical…and quarantine for Ebola was not

Measles has come to the happiest place on Earth. As of this writing, a total of 32 cases of measles have been linked to Disneyland visits that took place between December 17th and 20th. About 75% of the cases identified to date were not vaccinated, either because they chose to forgo vaccines or because they were too young, and at least 6 have been hospitalized.

A measles outbreak is a public health disaster, which can cost into the millions of dollars in health resources. You can be sure that public health workers in California and beyond are working overtime trying to identify cases, educate those who were possibly exposed about how dangerous measles can be, and implement practices so that those who may have been exposed to measles don’t further put others at risk. This includes avoiding public places, and practices such as calling ahead to a doctor’s offices so possible cases can be ushered into private rooms rather than languishing in the waiting room. A clinic in La Mesa recently closed because of a potential measles exposure. An unvaccinated South Pasadena woman, Ylsa Tellez, received a quarantine order after her younger sister was diagnosed with measles. Tellez is fighting the order and “taking immune-boosting supplements” instead.

Why such extreme measures on the part of public health?

Measles is highly contagious. It’s spread by air, and so contagious that if an infected person enters a room, leaves, and an unvaccinated person enters the room hours later, they still can contract measles. Remember a few months back, when that figure was circulating showing that Ebola wasn’t particularly easy to spread? Well, measles very much is. The basic reproductive rate for Ebola is around 2, meaning on average each infected person will cause an additional 2 infections in susceptible individuals.

And what’s the reproductive number for measles?

Eighteen. Eight. Teen. I’m not exaggerating when I say that it is literally one of the most contagious diseases we know of.  On average, if you have 10 susceptible individuals exposed to a measles patient, 9 will end up getting sick.

How do we break the cycle of transmission? Vaccination is one way–if one has been vaccinated for measles, chances are very low (but not zero, because nothing is perfect) that they will contract measles. Beyond vaccination, the next-best intervention is to keep those who are infected away from everyone else. The way we do this is by quarantining them.

In public health terms, quarantine specifically refers to the separation of individuals who have been exposed to an infectious agent, *but are not yet ill themselves,* from the rest of society. That way, they’re unable to spread the infection to others. Quarantine makes the most sense when individuals can transmit the infection before they realize they’re sick, which is exactly the case with measles. Infected individuals can spread the virus fully 4 days before the characteristic rash starts to appear, and continue to spread it for another 4 or so days after the rash begins—potentially infecting a lot of people. The problem is, like Ylsa Tellez, they’ll feel fine while they’re out there in the general population. They don’t even have to be coughing or sneezing to spread it (symptoms which can appear prior to the rash)—they can just be breathing (something many of us like to do on a regular basis), and still contaminate their environment with the measles virus.

The difference in transmissibility also makes measles a very different situation from Ebola. Public health officials almost universally condemned quarantine for Ebola exposures, for two reasons: 1) Ebola wasn’t highly transmissible, and  isn’t airborne like measles is; and 2) because Ebola isn’t efficiently transmitted until late in the infection when the patient is very ill and likely bedridden. Quarantining Ebola patients was a political stunt, not a public health necessity.

This is why states have the legal authority to enforce quarantine for infectious diseases: it reduces the risk that asymptomatic, potential disease-spreaders will act as “Typhoid Marys” (another asymptomatic, deadly-disease-spreader), which is in the public interest. And while unvaccinated Tellez feels “attacked” and her mother thinks people are being “not nice” when they demand that Tellez submit to quarantine, their choice not to vaccinate has already put many others at risk of disease and, and is resulting in the quarantine of many other exposed individuals as well. In the 2011 Utah measles outbreak, 184 were quarantined and thousands of contacts traced, at an expense of approximately $300,000. The Disneyland outbreak has already spread into 4 states (California, Utah, Washington, and Colorado). Quarantine is one of our tools to stem the epidemic. In our recent outbreak among Ohio Amish, most willingly submitted to quarantine, and over 10,000 doses of the MMR vaccine were administered. Quarantine is undoubtedly a difficult prospect to face, but perhaps if Tellez and others had been vaccinated in the first place, they, and we, wouldn’t be in this situation.

Why I vaccinate my kids

Being a new parent is exhausting. All of a sudden, you’re out of the hospital and on your own with this amazing, tiny human, and you alone are responsible for her care. You’re given reams of paperwork about feeding and sleeping, developmental milestones, red flags to look out for. You’re inundated with information you barely have time to look at. Mom is trying to heal from childbirth while barely sleeping, while her partner is trying to pick up the slack and pitch in as much as possible. You both fumble with the car seat, thinking that NASA must have equipment that’s easier to figure out. You obsessively check your sleeping baby to make sure she’s still breathing. You worry about every sneeze and try to decipher her cries. Is the diaper too tight? Is this acne normal? What do I do about her poor dandruffy head?

Do I vaccinate?

vaccineWilliam receiving the first of  his 2-month vaccinations

I know it can be scary. You might have heard from friends or relatives, or read on the internet, that vaccines can harm your baby. You may be concerned about autism, or think that “natural immunity” is better than that which develops from injections. You may think that the diseases she’s being vaccinated against “aren’t all that bad,” or that kids today receive too many vaccines. You might feel that your physician is “bought out” by “big Pharma” and that your health care providers are writing off your concerns.

I know you just want to do what’s best for your child. I feel you. I’m the parent of a teenager, a tween, and a 2-month old. Here is why I vaccinate my children.

William vax 2William receiving his vaccinations

I’ve spent almost 20 years of my life studying infectious diseases up-close and personal, not from random websites on Google. I’ve worked with viruses and bacteria in the lab. I respect what germs are capable of. I worry about vaccine-preventable diseases coming back because of low levels of herd immunity. I cry over stories of babies lost to pertussis and other vaccine-preventable diseases. As I’ve noted before, chicken pox has played a role in the deaths of two family members, so I don’t view that as just a “harmless childhood disease.” Vaccines have eradicated or severely reduced many of the deadliest diseases from the past: smallpox, polio, measles, diptheria.

But that’s not the only reason I vaccinate. I vaccinate because I’m all too aware of the nasty diseases out there that still don’t have an effective vaccine. My current work focuses on a germ called methicillin-resistant Staphylococcus aureus (“MRSA”), a “superbug” which kills about 11,000 people every year in the United States. We have no vaccine. I previously worked on two different types of Streptococcus: group A and group B. Group B is mainly a problem for babies, and kills about 2,000 of them every year. It leaves many others with permanent brain damage after infection. We have no vaccine. Group A kills about 1,500 people each year in the U.S. and can cause nasty (and deadly) infections like necrotizing fasciitis (the “flesh-eating disease”). We  have no vaccine. These are all despite the fact that we still have antibiotics to treat most of these infections (though untreatable infections are increasing). Infectious diseases still injure and kill, despite our nutritional status, despite appropriate vitamin D levels, despite sanitation improvements, despite breastfeeding, despite handwashing, despite everything we do to keep our kids healthy. This is why protection via vaccination is so important for the diseases where it’s available. If vaccines were available for the diseases I listed above, I’d have my kids get them in a heartbeat.

w after vax 1William with daddy, right after finishing his vaccinations

I’ve done my best to keep my kids healthy and safe. I nag about bicycle helmets and make sure they’re getting exercise. I make them eat vegetables. I don’t move the car until everyone is buckled up. My older kids were in booster seats for what felt like forever, as both were on the small size for their age. Vaccinations are just one more part of this arsenal. I’m well versed in the safety data and know that most vaccine side effects are minimal (fever, soreness at injection site). They don’t cause autism, or SIDS, or any of the other claims made by dubious sites such as Natural News or Mercola. They do save lives and prevent disease by training the body to recognize and fight germs.

My youngest recently went in for his 2-month shots. He cried a bit when he received them, but not any worse than he does when he needs to be burped, changed, or held. He slept a little extra that evening, but was back on his normal schedule the next day. At his visit, he received the oral rotavirus vaccine; his second Hepatitis B shot; his pneumococcal vaccination; and the combination shot including diptheria, pertussis, tetanus, polio, and Haemophilus influenzae (DTaP/polio/Hib). Each one I see as a small measure to support his health and safety, as well as my own peace of mind, knowing that I did what I could to protect him from infections that used to kill thousands of children every year. Some still do when vaccination isn’t available or accepted–measles killed over 120,000 people in 2012, most of them young children who hadn’t been vaccinated.

W after vax 3William at home after his vaccinations

We all try to do the best by our children. As a scientist who’s studied infectious diseases, vaccination is a no-brainer for me, and I worry for the children out there who are left undefended against these infections because of misinformation and wrongly-placed fears. I know these parents are trying to do right by their kids, but infectious diseases don’t recognize good intentions. As I sit here with my baby breathing softly beside me, I am thankful for those who came before me and dedicated their lives to protecting children like him, and grateful that he will never have to suffer from infections that were the scourge of earlier generations.

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Is history repeating itself?

This is the fifteenth of 16 student posts, guest-authored by Cassie Klostermann. 

One of the major accomplishments that public health professionals pride themselves in is the reduction of people getting sick or dying from preventable infectious diseases. Unfortunately, these debilitating, historic diseases that health professionals had once thought they had under control are starting to rear their ugly heads once again in the United States (U.S.). One of these diseases that I am referring to is measles. Measles is a highly contagious virus (from the genus Morbillivirus) spread through the air when an infected person coughs or sneezes making measles extremely easy to get by being around someone who is sick with this disease. According to the Centers for Disease Control and Prevention (CDC), if someone has the measles virus they could potentially infect 9 out of 10 people they come in contact with who are not immune (i.e. not vaccinated) to the disease.

Some of the most common symptoms associated with measles are fever, runny nose, and cough which are also very similar to the symptoms of many other diseases. Measles also commonly causes a rash that can cover the entire body. Those who have measles can spread the virus to another person about 4 days before and after the rash shows up. There are also a few more rare but more serious complications that can develop from having the measles virus such as pneumonia and encephalitis and it can also lead to the death of those infected.

The word measles comes from the Middle Dutch word masel meaning “blemish.” The history of measles cases goes relatively far back into history with references of the virus appearing in records as early as 700 AD. In the U.S., before the vaccine was introduced in 1963, there were about 3-4 million cases (essentially every child had had the disease by the time they were 15 years old), about 1,000 people suffered deafness or permanent brain damage (from encephalitis, for example) and around 450 people died from measles each year. By 2000, naturally occurring cases of measles in the U.S. (meaning cases that originated in the U.S. rather than another country) had been eliminated, although there are normally about 50 measles cases per year in the U.S. that come from other countries where measles is endemic (or constantly present in their population) and with increased worldwide travel people need to be more aware of their risk for contracting measles. Throughout the world, there are an estimated 20 million cases leading to about 164,000 deaths from measles each year, which is a great improvement from the 2.6 million deaths that occurred before the measles vaccine was globally used. The number of measles cases, long-term diseases, and deaths caused by measles are going down year by year and much of this progress can be attributed to efforts that provide the measles vaccine worldwide.

While the overall number of measles cases throughout the world are decreasing (mostly from decreasing cases in developing countries) the U.S. and other developed countries are seeing the opposite trend. According to the Notifiable Diseases and Mortality Tables from the Morbidity and Mortality Weekly Report, there were 223 reported cases of measles for 2011 occurring over 17 outbreaks in the U.S. (the average number of outbreaks is 4). This is an increase from previous numbers (63 cases in 2010 and 71 cases in 2009, to name a couple) and the majority of people infected, about 65%, had not been vaccinated against measles even though most of them were eligible to get the vaccine. Out of the measles cases seen in 2011, 90% were traced back to measles viruses seen in endemic countries and brought back to the U.S. where it was spread person to person in the States. Even though historically measles cases have been high in developing countries (especially Africa and Asia) extensive immunization programs have greatly decreased the amount of cases per year. Now European countries are seeing a large increase in their numbers of measles cases since 2009 because the number of vaccinated people has decreased.

The only proven way to effectively protect someone against contracting measles is to get the MMR (measles, mumps, and rubella) vaccine. If you have not been vaccinated then you are leaving yourself vulnerable to getting the diseases included in the MMR vaccine. This issue doesn’t just stop with the individual person, it spreads to everyone that individual comes into contact with. As mentioned above, measles is highly contagious and is spread through the air when an infected person coughs or sneezes so it can easily infect anyone breathing the same air you breath that is also vulnerable to the disease. When people who are vulnerable to getting the disease breathe in the contaminated air, they have a fairly high chance of getting measles and it is important to keep in mind that there are people who cannot get the MMR vaccine because they are either too young (under 12 months old), too sick (i.e. cancer patients), or the elderly who may have lost some of their immunity. For these people, they do not have a choice as to whether or not they get the vaccine, but they still deserve to have some protection from diseases prevented by vaccines. This protection comes from a concept referred to as herd immunity where there are enough people in a community or country vaccinated against a disease so that is unable to be “kept alive” because there not enough vulnerable people for it to pass through. If we are able to keep herd immunity up high enough by having enough people vaccinated against the measles, then the number of measles cases per year could drop back down to the normal 50 per year instead of 220 per year.

Travelers especially need to keep in mind that although a disease, like measles, is usually a rare occurrence in the U.S., this is not the case in many other countries in Europe, Asia, and Africa as examples. People traveling to countries where measles is endemic really should consider being vaccinated because their risk of being infected is much greater due to the higher number of people in the country infected with the disease.

As with anything in medicine, vaccines can cause reactions in rare situations and I urge people to ask their healthcare provider any questions they have regarding the MMR vaccine. I also urge people to receive all of the recommended vaccines they can (unless they have had past allergic reactions to a specific vaccine) because the risk of contracting measles and dying from it is more common than having a more moderate reaction to the MMR vaccine. If you or your kids are eligible to receive the MMR vaccine, please, please get vaccinated and talk to your doctor if you have concerns about an allergic reaction. By getting vaccinated you are not only protecting yourself and your children but also those who are unable to get the vaccine to protect them from the measles. If vaccination rates do not improve, we may very well see case numbers approach historical highs present before the vaccine was used.

References

http://www.cdc.gov/measles/about/overview.html

http://www.cdc.gov/measles/about/transmission.html

http://wwwnc.cdc.gov/eid/article/12/4/et-1204_article.htm

http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6104a3.htm?s_cid=mm6104a3_w

http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6122md.htm?s_cid=mm6122md_w

http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6115a1.htm?s_cid=mm6115a1_w

http://www.who.int/mediacentre/factsheets/fs286/en/

http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6047a1.htm

http://www.niaid.nih.gov/topics/pages/communityimmunity.aspx

http://www.cdc.gov/measles/travelers.html

http://www.cdc.gov/vaccinesafety/Vaccines/MMR/MMR.html

http://www.aap.org/en-us/about-the-aap/aap-press-room/Pages/Protect-Children-from-Vaccine-Preventable-Diseases-Including-Measles-.aspx

http://www.immunizationinfo.org/vaccines/measles

 

Hemolytic uremic syndrome (HUS) in history–part 4: the bigger picture

As I’ve laid out this week (part 1, part 2, part 3), the realization that a fairly simple, toxin-carrying bacterium could cause a “complex” and mysterious disease like hemolytic uremic syndrome came only with 30 years’ of scientific investigation and many false starts and misleading results. Like many of these investigations, the true cause was found due to a combination of hard work, novel ways of thinking, and simple serendipity–being able to connect the dots in a framework where the dots didn’t necessarily line up as expected, and removing extraneous dots as necessary. It’s not an easy task, particularly when we’ve had mostly culture-based methods to rely on since the dawn of microbiology.

If you read start digging around in the evolutionary medicine literature, you’ll see that one oft-repeated tenet is that many more “chronic” and “lifestyle” diseases are actually caused by microbes than we currently realize. (I’ll note that there is active disagreement here in the field–one reason noted is that many of these diseases would decrease one’s fitness and thus they are unlikely to be genetic, but many of them also have onset later in life than the prime reproductive years, so–still controversial). But whether you agree on the evolutionary reasoning or not, I think it’s safe to say that those who make this claim (like the Neese & Williams book I linked) are probably right on the overall assertion that more and more of these “lifestyle/genetics” diseases are going to be actually microbial in cause than we currently realize.

Why do I agree with this claim? History is a great indicator. Many infectious diseases were thought to be due to complex interactions of genetics (or “breeding,” “lineage,” etc.) with “lifestyle.” Think of syphilis and tuberculosis in the Victorian era. Syphilis (and many other diseases which we know now to be sexually-transmitted infections) was considered a disease which affected mainly the lower social classes (“bad breeding”), and was thought to be rooted in both family history as well as an over-indulgence in sex or masturbation. Tuberculosis, because it affected those throughout the income spectrum, was still blamed on “poor constitution” in the lower classes, but was a disease of the “sensitive” and “artistic” in the upper classes. It was also thought to be due to influences of climate in combination with genetics. Or, look to more recent examples of Helicobacter pylori and gastric ulcers, which were also ascribed to dietary habits and stress for a good 30 years before their infectious nature was eventually proven. And from that same era, HIV/AIDS–which even today, some are still all too ready to write off as merely a behavioral disease, rather than an infectious one.

So, we still view many of these diseases of unknown etiology as multi-factorial, “complex” diseases. And undoubtedly, genetic predisposition does play a role in almost every infectious disease, so I’m not writing off any kind of host/pathogen interplay in the development of some of these more rare sequelae, such as HUS as a consequence of a STEC infection. But looking back over history, it’s amazing how many diseases which we view now as having a documented infectious cause were studied for years by researchers thinking that the disease was the result of exposure to a toxin, or diet, or behavior, or a combination of all three.

I’ve mentioned the example of multiple sclerosis in previous posts. Multiple sclerosis is an autoimmune disease; the body produces antibodies that attack and eventually destroy parts of the myelin sheath covering our nerves. The cause of MS, like HUS 40 years ago, is unknown, though it’s thought to be a combination of genetics and environmental influences. Going through the literature, it seems like almost everything has been implicated as playing a causal role at one point or another: pesticides, environmental mercury, hormones, various other “toxins,” and a whole host of microbes, including Chlamydia pneumoniae, measles, mumps, Epstein-Barr virus, varicella zoster (chickenpox), herpes simplex viruses, other herpes families viruses (HHV-6 and HHV-8), even canine distemper virus. They’ve done this looking at both microbe culture (from blood, brain tissue, CNS, etc.) as well as using serology and DNA/RNA amplification in various body sites. None have shown any strong, repeatable links to the development of MS–much like the spurious associations that were seen with adenovirus and HUS.

Although no microbial agent has been convincingly implicated to date, there are tantalizing hints that MS is caused by an infectious agent. There have been “outbreaks” of MS; the most famous occurred in the Faroe Islands in the 1940s. Studies of migrants show that the risks of developing MS seem to be tied to exposures in childhood, suggesting a possible exposure to an infectious agent as a kid. And one of the most common mouse models used to study MS has the disease induced by infection with a virus called Theiler’s murine encephalitis virus (TMEV). If it can happen in mice, why not humans?

It might seem implausible that infection with some microbe could lead to the eventual neurological outcomes of MS, but again, examples abound of weird connections between microbes and health outcomes. For STEC, it might not be intuitively obvious at first glance how a fecal organism could be a cause of kidney failure. The respiratory bacterium Streptococcus pyogenes usually causes throat infections (“strep throat”), but if left untreated, it can also cause kidney damage (glomerulonephritis) or even heart failure due to rheumatic heart disease. A microbial cause of MS could lie in a virus, bacterium, parasite, or fungus–maybe one that we haven’t even discovered yet, but that perhaps will pop up as we learn more and more about our metagenome. Perhaps 30 years down the road, the way we view many of these “complex” diseases will look as short-sighted as it does looking back at old HUS papers from today’s vantage point.

Measles in Iowa

We’ve had pertussis and mumps, so it was only a matter of time.

State health officials declared a “public health emergency” Tuesday after a test confirmed a case of measles in an unvaccinated Dallas County baby who apparently picked up the disease in India.

They said people who might have been exposed included passengers on an Americans Airline flight from Chicago to Des Moines May 11 and people who were at Mercy Medical Center or a Mercy pediatric clinic in downtown Des Moines May 14.

Dr. Patricia Quinlisk, medical director for the Iowa Department of Public Health, said many Americans falsely recall measles as a benign childhood illness. “I get asked by medical students, ‘Which disease are you most afraid of?’ And they expect me to say Ebola or SARS or something like that – but, it’s measles,” she said. “I don’t think people understand how bad it can be, how many people can get seriously ill and, unfortunately, how many people can die from this disease. It’s bad and it’s probably the most spreadable disease we have in our society.”

***

Dr. Asha Madia, a Mercy pediatrician, said the patient is an 8-month-old boy who had a fever, a rash and a mild eye infection. He has recovered. She said the boy was not vaccinated because such vaccinations generally are not given before age 1. But she said his family believes in vaccinations and had immunized the boy’s older sibling.

So this is unique in that the index case isn’t from a family who has eschewed vaccination (unlike this case in 2004), but in a child who was unvaccinated nevertheless due to his age. This is one reason the CDC just last month recommended the MMR vaccine in infants who would be traveling abroad, even if they are below the traditionally recommended age.

Story still developing, but for now it appears that this is the only case recognized. However, as Maryn recently pointed out, *any* measles outbreak isn’t cheap, due to the diligent surveillance that must be undertaken to make sure no one else comes down with the infection. Full information available here from the Iowa Department of Public Health.

The consequences of refusal

I’ve written previously about “chicken pox parties”. These types of events are coming back into vogue (they were common in the days before the vaccine, when the only way to provide immunity was to be infected), as parents mistakenly believe that “natural exposures” to these pathogens are somehow superior–and safer–than vaccinations. Though the latest rage are “H1N1 parties”, chicken pox parties are still around, and potentially being held at your local McDonald’s by families connecting on the internet:

I am trying to put together a chicken pox party and am looking for someone to donate their chickenpox to the event.
I was thinking of having it at McDonald or some place with toys to play on.
if you know anyone who would like to contribute or would like more information on a time and place let me know.

This is, again, one of my biggest problems with those who refuse vaccines. They frame the issue as solely “my child, my choice.” Which is fine, until you put that child in with the rest of society via school, or daycare, or even trips to McDonald’s. These interactions include infants who are too young to get vaccinated; people with chronic conditions or who are receiving chemotherapy, and are therefore more susceptible to disease; or those in whom the vaccine just didn’t “take” (my own measles titers were not high enough to be protective, I learned last year when I was preparing to go to Mongolia–despite having 2 doses of the vaccine), and on and on. Yes, you have the right to make decisions for your child–but parents should realize that this particular choice can put a lot of others in danger.