infectious disease

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How Contagious Is That Dinner Party? And How Best To Evade Friends’ Bugs?

(Faruk Ateş/Flickr)

(Faruk Ateş/Flickr)

“This is not a question for an expert on etiquette!” I expostulated. “It’s a question for an Infectious Disease specialist!”

The trigger for that objection: A query to Social Qs, the New York Times etiquette column on “awkward situations.” The writer describes a group of 10 close friends who meet regularly for dinner; one, who is immuno-suppressed, asks that another member who is getting over the flu and still on antibiotics keep 12 feet away and avoid touching anything she may eat. The reader asks: “Shouldn’t one of them have declined the invitation? But which?”

The columnist responds that no, no one needed to bow out, and that this distance-setting arrangement seems a good compromise, adding, “I hope the person with the flu called her doctor to make sure she was no longer contagious — for everyone’s sake.”

Surely you can understand my frustration. Fine, the flu patient could call her doctor, but what about the rest of us, hungry for more general knowledge on contagion for our own social gatherings? Why not answer the obvious questions? Like: Is 12 feet really far enough to avoid flu germs? Are you still contagious when you’re finishing a course of antibiotics?

Oddly, the day after I read that column, a similar situation played out at my house: One friend was getting over a respiratory infection, still coughing, and another friend regretfully said she could not stay and chat at the dining table, for fear of carrying a germ to an immuno-compromised loved one.

That did it. I called CommonHealth’s go-to guy on infectious disease questions of public interest, Dr. Ben Kruskal, chief of infectious diseases at Harvard Vanguard Medical Associates, and shared my annoyance. Actually, he gently corrected me, this is an issue of both medical science and etiquette. Our conversation, lightly edited:

Dr. Kruskal: You need to have the facts and then you can figure out the etiquette in light of them.

First, when it come to infectious disease transmission, we know a fair amount, but there’s a lot that is still argued over. So let’s take flu as a good example. We know that there are multiple mechanisms by which flu is transmitted, or by which you could postulate reasonably that it might be transmitted:

Dr. Ben Kruskal (Courtesy)

Dr. Ben Kruskal (Courtesy)

• Physical contact: You’ve got germs on your hands, you touch somebody else’s hands or face. Or indirect contact — you touch your face, and then touch the doorknob. A few minutes later, someone else touches the doorknob and then their face.

And there are two different mechanisms of airborne transmission:

• Respiratory droplets, which fall to the ground pretty quickly after they leave your mouth and nose. People argue about the distance they can travel — some people say three feet, some say six feet. Six is a very conservative estimate.

• And then there’s what’s called true airborne transmission (technically, droplet nuclei), which is the mechanism by which TB, measles and chicken pox are all transmitted. And that’s the kind that can go much longer distances and can linger in the air for a long time afterward.

So which is flu?

Flu looks like it’s probably mostly droplets, with some contact, and then there’s a lot of debate in the medical literature about whether there’s some component of airborne transmission or not. If it’s there, it’s probably not huge — we’re arguing whether it’s .1 percent or 1 percent or 5 percent, but it’s probably not more than that.

What else should we know? Continue reading

5 Reasons You Should Worry Way More About Flu Than Ebola

(CDC)

(CDC)

By Veronica Thomas
Guest Contributor

A deadly virus is sweeping America, putting nearly 10,000 people in the hospital so far. No, it’s not Ebola. We’re talking about the common seasonal flu that shows up every fall and lingers on until spring.

Every year, 5 to 20 percent of Americans get the flu and, depending on the strain, anywhere from 4,000 to 49,000 people die from the virus or its complications, like pneumonia. And this season’s flu virus is shaping up to be pretty nasty — so nasty that the CDC declared a national flu epidemic at the end of December.

As a graduate student at the Harvard School of Public Health, I’m baffled by this: A couple months ago, I couldn’t step on a subway car or flip through Facebook without being bombarded by panicked comments about Ebola spreading to the U.S. But when it comes to the real and immediate threat of the flu: radio silence.

“Ebola is exotic. It has a very high mortality rate that people are very much aware of. It seems like you can be exposed to it without your control,” says Dr. Alfred DeMaria, medical director for the Bureau of Infectious Disease at the Massachusetts Department of Public Health. “All of those [factors] contribute to a higher perception of risk than the flu.”

In reality, far, far more people die from flu-related complications than from Ebola, but it’s a very small proportion of the millions who get sick each year. That’s one reason we should be more concerned about the flu than Ebola, Dr. DeMaria says. Here’s why else:

1) The flu is next door, not across the Atlantic.

Ebola has tragically claimed over 8,600 lives in West Africa, largely because many countries don’t have the capacity to contain the outbreak or treat infected patients. And though the news cycles have moved on, Ebola hasn’t. As the virus continues to spread, Ebola remains a real threat for some West African countries.

But for ordinary Americans: “The risk of getting Ebola is somewhere in the order of magnitude of getting personally hit by a meteorite,” Dr. DeMaria says. Just four people have been treated for Ebola in the U.S., and only one has died. No new cases have been reported since October. Continue reading

Quick, Take Tamiflu? Maybe Not A Slamdunk If You’re Young And Healthy

(Photo via Compfight.com)

(Photo via Compfight.com)

As I listened to CDC director Dr. Tom Frieden issue a ringing endorsement of the prescription antiviral drug Tamiflu last week, I was also hearing a confused “But…but….but…” in my own head.

The crux of my confusion: I had the decided impression that the data on Tamiflu as a flu-fighter were underwhelming. That it just isn’t all that effective. That doctors prescribe it because they have nothing better, but without a lot of hope that it will do a lot of good.

Among the factors that formed that impression:

• A MedPage Today post last month headlined “Why Is Tamiflu Still Around?” with the subhead, “Tamiflu doesn’t help, so why are docs still prescribing it?”

• The data-driven doctors who run the Slow Medicine series had written last week that they accepted the updated CDC guidelines recommending quick antiviral therapy for high-risk patients. But….

“…as for patients who were previously healthy with less severe disease, we are more skeptical. The CDC recommends consideration of antivirals among such patients if the medications can be started within 48 hours of symptom onset. However, we suspect the side effects of antiviral medications are greater than the pharmaceutical companies have let on (identification of adverse effects for short term medications is particularly difficult). In most cases, good supportive care with close follow up will be more helpful than a marginally effective medication with uncertain side effects with attendant risks of future resistance.”

• And Dr. Ben Kruskal, chief of infectious diseases at Harvard Vanguard Medical Associates, had recently responded to my email query about Tamiflu with this:

“My enthusiasm about antivirals for flu is mixed. They’re the best tool we have, but the evidence for the most hoped-for benefits is scanty indeed.”

Bottom line? Dr. Frieden’s bottom line was simply that antivirals are under-used and if a member of his family got the flu, he’d want them treated with Tamiflu. But the chief of the CDC has to think at the level of a whole population; what about those of us who think at the level of an individual?

You may prefer a more nuanced take from the likes of the Slow Medicine analysts and Dr. Kruskal, to wit:

Maybe the real Tamiflu bottom line here is that there’s no simple bottom line.

Yes, if the patient is elderly or a baby or severely ill or otherwise at high risk of flu complications for any number of underlying health conditions — asthma, diabetes, cancer — quick prescription of antivirals (Tamiflu, Relenza and a new intravenous form, peramavir) makes sense. The potential dangers of flu complications in such high-risk patients are especially scary, so the potential benefits from the antivirals loom larger.

But if the patient is otherwise healthy, Dr. Kruskal says, while it’s a reasonable decision to take Tamiflu, “I wouldn’t call it entirely a slam-dunk.” Continue reading

In Tough Flu Year, CDC Touts Prompt Tamiflu Prescriptions

(Photo via Compfight.com)

(Photo via Compfight.com)

Note: We’ve also posted a follow-up to this news story: Quick, Take Tamiflu? Maybe Not A Slamdunk If You’re Young and Healthy.

Flu seasons are never good, but this year’s is shaping up as a notably nasty one. It’s dominated by a strain of virus — known as H3N2 — that tends to cause more severe symptoms and is a poor match for this year’s vaccine. And we’re still right in the middle of it.

So today, CDC director Dr. Tom Frieden issued this new, Tamiflu-touting message to reporters and the public: “Anti-viral flu medications are greatly under-utilized. But if you get the flu, and if you get medicines early, they could keep you out of the hospital; they could keep you from having to go into the intensive care unit; and they might even save your life.”

If I or one of the members of my family got flu or a flu-like illness, I would get them or me treated with Tamiflu as quickly as possible.

– CDC director Dr. Tom Frieden

That message is especially important, he says, for people at high risk for complications of flu, including elders over 65, pregnant women, very young children and people with underlying health issues such as asthma or diabetes. The anti-virals work best if taken within the first 48 hours of flu onset.

In case you’re now feeling an urge to run out and stock up on Tamiflu, well, first of all, you can’t. Tamiflu and its ilk are available only by prescription.

And second, you shouldn’t. It would make you a bad citizen. Frieden reports that though manufacturers have a big enough supply overall, there are spot shortages of Tamiflu around the country, and it may already take some calling around to find a pharmacy with a supply. Stockpiling could deprive patients who need the drug more than you do.

Dr. Alfred DeMaria, medical director for the Bureau of Infectious Disease at the Massachusetts Department of Public Health, says a local pediatrician recently told him about prescribing an antiviral drug for a Cystic Fibrosis patient at high risk for flu complications. The family had to go to several pharmacies before they could fill the prescription.

“Why was that? The pharmacies have just-in-time inventory for expected sales,” Dr. DeMaria says, “and if those expected sales go up because people say, ‘Oh, it’s going to be a bad flu season; they’re recommending Tamiflu; I’m going to get some and keep it just in case,'” then supplies run short.

The new CDC recommendations encouraging health care staffers to write more antiviral prescriptions may surprise those familiar with less-than-exciting reports on how effective the drugs can be. In general, if taken early, they appear to cut the flu’s duration by 20 percent, from an average of five days to four. Continue reading

Reality Check: How People Catch Ebola, And How They Don’t

Dr. Elke Muhlberger (Courtesy of Kalman Zabarsky for BU Photography)

Dr. Elke Muhlberger (Courtesy of Kalman Zabarsky for BU Photography)

It’s confusing. You hear that Ebola victim Thomas Eric Duncan was so contagious that two Dallas nurses in protective gear caught the virus. But then you hear, in more recent days, that apparently nobody else did, including the inner circle who lived with him and cared for him. The CDC announced today that all of Mr. Duncan’s “community contacts” have completed their 21-day monitoring period without developing Ebola.

How to understand that? And how to address alarmists’ claims that for the nurses and so many West Africans to have caught Ebola, it must have gone “airborne”?

I turned to Dr. Elke Muhlberger, an Ebola expert long intimate with the virus — through more than 20 years of Ebola research that included two pregnancies. (I must say I find this the ultimate antidote for the fear generated by the nurses’ infections: A researcher so confident in the power of taking the right precautions that she had no fear — and rightly so, it turned out — for her babies-to-be.)

Dr. Muhlberger is an associate professor of micriobiology at Boston University and director of the Biomolecule Production Core at the National Emerging Infectious Diseases Laboratories (widely referred to as the NEIDL, pronounced “needle”) at Boston University. Our conversation, lightly edited:

Is it really true you worked on Ebola through two pregnancies?

Yes, but in the proper protective gear. That makes a huge difference, if you’re protected, if you know how to protect yourself, and that is the case in a Biosafety Level 4 lab, of course. If you compare the protective gear we’re wearing in a Biosafety Level 4 lab and the gear they’re wearing in West Africa now treating patients, it’s like comparing a stainless steel vault to a cardboard box.

But on the other hand, if you look at the nurses in Dallas, you say, ‘How did they get infected?’ It makes you worry that maybe protective gear isn’t good enough — but you’re proof of the opposite.

A Biosafety Level 4 lab is such a high-end lab, it is not possible to use protective gear like that in every hospital in the U.S.

Could you please lay out a brief primer on the biology of how Ebola is transmitted?

We know from previous outbreaks, and also from the current outbreak, that Ebola is transmitted by having very close contact to infected patients. So we know that it is transmitted by bodily fluids, which include blood, first of all — because the amount of virus in the blood is very, very high, especially at late stages of infection — but it’s also spread by vomit, by sputum, by feces, by urine and by other bodily fluids.

The reason for that is that at late stages of infection, the Ebola virus affects almost all our organs — it causes a systemic infection. One main organ targeted by Ebola virus is the liver, and that could be one of the reasons that we see these very high concentrations of viral particles in the blood. But I would like to emphasize that that occurs late in infection.

Early infection is the other way around. The primary targets — the first cells that come in contact with Ebola virus and get infected — are cells that are part of our immune system. And these cells most likely spread the virus throughout our body. But there are not so many cells infected at the very beginning of the infection, which might be the reason why Ebola virus patients do not spread virus at the very beginning of infection. And that’s why it’s safe to have contact with these patients, because the viral titers in their blood are so low that we cannot even detect them with methods like PCR, which is one of the methods we use to diagnose Ebola virus.

Is a virus only contagious when it reaches a certain level of “titer” or load? Continue reading

Harvard Poll On Ebola Risk Finds Public Dazed And Very Confused

A World Health Organization worker trains nurses on how to use Ebola protective gear in Freetown, Sierra Leone. (AP)

A World Health Organization worker trains nurses on how to use Ebola protective gear in Freetown, Sierra Leone. (AP)

By Richard Knox

Americans are seriously confused about how Ebola spreads. And it’s no wonder.

A new national poll from the Harvard School of Public Health finds that nearly 9 out of 10 Americans think someone can catch Ebola if an infected person sneezes or coughs on them.

Not so, according to all health authorities and 38 years of research on this virus. But maybe people can’t be blamed for thinking Ebola can be spread through the air as they see powerful images day after day of health workers clad in head-to-toe protective coverings and face masks.

And there’s little to no possibility that Ebola will mutate into a virus easily spread by aerosol droplets, like influenza or SARS, for reasons that Laurie Garrett of the Council on Foreign Relations recently pointed out in The Washington Post.

Similarly, all the attention on the imported Ebola case of a Liberian man in Dallas and subsequent infection of two of his nurses (so far) is apparently leading many Americans to overestimate their risk of getting the virus.

In contrast, the great majority (80 percent) think they’d survive Ebola if they got immediate care. That’s probably right — though no sure thing.

(Courtesy of Harvard School of Public Health)

(Courtesy of Harvard School of Public Health)

The Harvard poll, conducted between last Wednesday and Sunday, finds that a little over half of Americans worry there will be a large outbreak of Ebola in this country over the coming year.

More than a third worry they or someone in their immediate family will get Ebola. Continue reading

Curb Your Hysteria: Talking Rationally To Kids About Ebola Risk

A man diagnosed with Ebola this week is being treated at Texas Health Presbyterian Hospital in Dallas. (AP)

A man diagnosed with Ebola this week is being treated at Texas Health Presbyterian Hospital in Dallas. (AP)

By Gene Beresin, MD and Steve Schlozman, MD

On Sept. 30 the first case of Ebola was diagnosed in the United States. The patient, who is currently being treated in Dallas, had recently traveled to Liberia, and was back in this country for a few days before symptoms began.

Understandably, the coverage of this news is pervasive. Although it seemed inevitable that a case in the U.S. would eventually emerge, the story still ignites a fair bit of hand-wringing among just about everyone who has learned of it.

Additionally, our country has experienced some novel infections that have ignited increased concerns in recent weeks. Enterovirus D-68 has made its way across the nation, causing severe cold-like symptoms, and, in some children with conditions such as asthma, the need for hospitalization. There’s also a potentially new contagion on the horizon that appears to cause varying degrees of muscular paralysis, and may or may not be related to Enterovirus D-68.

But, as public health officials are eager to stress, a nuanced and thoughtful approach to these issues has been as necessary as it has been fleeting. Experts agree that our medical infrastructure is well-equipped to handle even a virus as scary as Ebola, and some doctors are quick to point out that viruses like respiratory syncytial virus (RSV) and influenza are much more likely to cause harm than these new ones.

This raises a critical point:

Ebola, as scary as it is, poses a relatively minor threat to the United States; and the current cases of Enterovirus D-68 are far out-numbered by the RSV and influenza cases we experience on a yearly basis. And the currently unknown contagion that appears to cause paralysis has only happened in a very small population of kids.

So why the massive reaction in the media and among worried parents? Intellectually, at least at this point, all indications point to little danger for our children and ourselves. Why, then, do we get so frightened?

Well, let’s start with this confession: We’re frightened.

Sort of.

We know, intellectually, that the threat is minor. But, when has intellect played a leading role in the emotionally driven process of threat assessment? And, especially with regard to infectious disease, when has anyone other than the most statistically driven scientists been able to preserve perspective? We’re not saying that we should massively worry, or even that we’ll be changing our instructions to our kids or our patients on how to behave with these new bugs dancing around.

What we’re saying is that germs, especially new germs, are scary. We have a long and probably evolutionarily derived tendency to fear disease, and when new ones rear their heads, we get alarmed.

Germs In Hollywood

As a society, we think about germs a lot — and nowhere, perhaps, does that play out more than in Hollywood. The 1954 novella “I am Legend” has been made into no less than three movies (“The Last Man on Earth,” “The Omega Man” and the more recent movie of the same title as the written work). You can rattle off other movies as well — there’s “Dawn of the Dead” (in 1978 and again in 2004), “Outbreak,” “Carriers,” “Contagion,” “The Crazies” (in 1973 and again in 2010),

“Quarantine” (and “Quarantine 2″) and most recently “World War Z.” You get the picture. Continue reading

Mass. Reports First Case Of Cold Virus, E68

Massachusetts has its first confirmed case of a cold virus that has sent hundreds of children to hospitals across the the country.

The case of an 8-year-old girl who was treated at Boston Children’s Hospital and released means Enterovirus 68 is here and spreading, says state epidemiologist Al DeMaria. It is not typically as dangerous as the flu, he says, except in children with asthma.

“Compared to influenza virus, this virus does not cause a lot of serious complications,” DeMaria said. “In fact, the vast majority of children who have asthma attacks get better.”

DeMaria urges children with asthma to take their management medications. He asks everyone to wash their hands often.

– Here’s the full press release from the state Health Department:

The Massachusetts Department of Public Health (DPH) today announced a confirmed case of Enterovirus D68. The patient is a school aged child with a history of asthma who became ill in early September and has since been treated and released from an area hospital. Due to privacy considerations, DPH will not be releasing additional patient information.

“With enterovirus D68 now widespread across the country, this news comes as no surprise,” said DPH Commissioner Cheryl Bartlett, RN. “We have been working closely with pediatric providers and area hospitals to ensure the proper testing was done to identify the virus. For most children, this virus is relatively mild – but for children with asthma or other respiratory illnesses, it can be serious. Parents should contact their pediatrician if their child is experiencing respiratory issues.”DPH State Epidemiologist Dr. Alfred DeMaria underscored the importance of simple, common-sense steps such as hand-washing to reduce the spread of illness. “As with any other respiratory virus, hand washing is the key to reduce spread, use soap and warm water for 20 seconds” said Dr. DeMaria.

Other tips for parents and patients include:
Avoid touching eyes, nose and mouth with unwashed hands
Avoid kissing, hugging, and sharing cups or eating utensils with people who are sick
Clean and disinfect frequently touched surfaces, such as toys and doorknobs, especially if someone in the home is sick

Continue reading

Ebola: As Other Doctors Die, Heading Straight Into The Outbreak To Help

Dr. Nahid Bhadelia is in protective gear with Dr. Guillermo Madico at the National Emerging Infectious Diseases Laboratory in Boston, where she directs infection control. This gear is slated to be donated to the Ebola-fighting efforts in Sierra Leone when she goes there in mid-August. (Jackie Ricciardi/BU Photo Services)

Dr. Nahid Bhadelia is in protective gear with Dr. Guillermo Madico at the National Emerging Infectious Diseases Laboratory in Boston, where she directs infection control. This gear is slated to be donated to the Ebola-fighting efforts in Sierra Leone when she goes there in mid-August. (Jackie Ricciardi/BU Photo Services)

If all goes as planned, Dr. Nahid Bhadelia will soon head straight into the heart of the Ebola outbreak that has already killed more than 700 people in western Africa, including at least 50 health care workers. Global and U.S. health authorities announced Thursday that they would ramp up efforts to bring the epidemic under control, but that it would likely take at least three to six months.

Dr. Bhadelia is director of infection control at the National Emerging Infectious Diseases Laboratory in Boston and a hospital epidemiologist at Boston Medical Center. She’s slated to travel to Sierra Leone in mid-August, to share her expertise on infection control and also care directly for Ebola patients. Our conversation, edited:

This is the biggest Ebola outbreak ever, as far as we know. Is it notable in other ways?

This is the first time Ebola has been present in these three countries: Sierra Leone, Guinea and Liberia. Because these countries haven’t seen the infection before, that impacted their ability to recognize and manage the infection early on.

Also, because of the recent travel of the American Patrick Sawyer to Lagos [where he died of Ebola], I think it has raised a lot more concern about transfer of Ebola abroad, which has not been much of an issue in the past.

A lot of the U.S. media coverage has focused on, ‘Could it come here?’ Part of that fear seems to stem from the sense that Ebola, with its hemorrhages and high death rate, is particularly horrible. Is it?

In some ways yes and in others no. Ebola Zaire, the strain we’re seeing right now, is one of the most deadly strains; it’s been shown in the past to have 90 percent mortality when no treatment is given. But in some ways, it’s much harder to transmit at a population level compared to respiratory viruses we’ve been hearing about such as SARS or MERS. It requires close contact with bodily fluids. So, for example, there’s been a lot of concern about travel of folks from the areas impacted to the developed world, and I think the reason it’s less likely to spread is because it’s limited to people who come into contact very closely with the person who’s impacted.

So many health care workers have been getting infected. Do you have a sense of why? Are there practices that might be easily correctable that you could have an impact on?

There are a lot of talented people there in the field already, not just from international organizations but people who’ve been working there a very long time. In Sierra Leone, for example, though they haven’t had Ebola before, they’ve dealt with Lassa fever, another viral disease that causes hemorrhagic fever, at Kenema — one of the places where Dr. Khan, the leading physician who just died of Ebola, worked. That center has dealt with Lassa fever for over 25 years, and there are nurses there who have long experience. The issue is the amount of patients. You have nurses there who were taking care of maybe a dozen Lassa patients and now they have to see 70 Ebola patients. I think the major issue is the fact that the health care system is so overwhelmed.

One of the major ways to alleviate that would be the presence of more personal protective equipment and more sterile medical equipment in general. I know that the PPE — the personal protective equipment — is a major concern because there’s a dearth of it right now in the field.

Also, we understand that the virus can be transmitted from surfaces — so if someone comes into contact with bodily fluids with the virus in them on a surface, that’s another way to get it. The virus can live outside the host for a couple of days. So this contamination of the environment is another important component — and that’s very difficult if you can imagine 70 patients in a small space. Ebola is not hard to kill, so it’s easy to avoid contamination in general. It’s only because of the number of people and poor health infrastructure that it becomes difficult.

Still, it’s so baffling that these leading, incredibly knowledgable doctors are getting infected. How can that happen? Continue reading

A Surprising New View Of Flu: Rethinking The 1918 Pandemic

Giving treatment to influenza patient at the U.S. Naval Hospital. New Orleans, Louisiana, Circa 1918. (Navy Medicine/Flickr)

Giving treatment to influenza patient at the U.S. Naval Hospital. New
Orleans, Louisiana, Circa 1918. (Navy Medicine/Flickr)

By Richard Knox
Guest Contributor

Ever since 1918, the world has wondered why a novel flu virus touched off an explosive pandemic that killed as many as 50 million people – most of them healthy young adults — and whether it could happen again.

Flu researchers today report some surprising news: They say the 1918 virus was no super-bug. Instead, its deadliness had to do with how very different it was from the flu viruses circulating 25 or 30 years before, when the young adults of 1918 were first exposed to the flu.

Indeed, the new study says it’s that first childhood exposure that determines how people will fight off – or fall prey to – every other flu virus they will encounter in a lifetime.

That’s a very different way of looking at flu, both pandemics and regular seasonal outbreaks.

Much of the current emphasis is on the virus itself. Scientists around the world are doing controversial “gain-of-function” experiments – adding and subtracting pieces of genes from flu strains to see what mutations make some viruses so virulent.

Instead of focusing on flu virus itself, authors of a paper published Monday in the Proceedings of the National Academy of Sciences say scientists and public health experts should pay attention to the vulnerabilities of different age groups to any new flu virus – and how those immune gaps might be filled in by targeted vaccine strategies.

“Childhood exposure seems to give kick-ass immunity to that kind of flu virus for many, many decades,” says evolutionary biologist Michael Worobey of the University of Arizona, the paper’s lead author. Continue reading