Effect Measure

Mask, gloves, gowns for a pandemic. Again.

Nonpharmaceutical interventions (NPIs) are in the news again. Yesterday was the dust up over Howard Markel and colleagues’ JAMA article from last August that appeared in CIDRAP News calling into question some of the historical data on the effectiveness of isolation and quarantine and now it’s an article in British Medical Journal that purports to show that some kinds of physical interventions like masks, gowns and handwashing might be better bets than vaccines and antivirals should a pandemic come our way:

Face masks and regular hand-washing are more likely to halt the spread of a deadly flu than all the antiviral drugs stockpiled worldwide, Australian experts say.

A global review has concluded that simple physical barriers will be more effective than drugs to prevent a pandemic of bird flu or another virulent bug.

The researchers from Australia, Italy, the US and the UK warn that combining measures like hand-washing and rigorous use of masks, gloves and gowns could be the best, and indeed only, line of treatment. (The Age [Australia])

All of this might well be true, but this paper is a pretty weak reed to lean upon. It was a systematic literature review of various studies that tried to gauge the effectiveness of a variety of practices in preventing the spread of respiratory infection. SARS and Respiratory Syncytial Virus (RSV) figure prominently but not influenza. Moreover the pertinent literature is for the most part neither abundant nor of high quality. From the paper’s Discussion section:

In this systematic review we found that physical barriers such as handwashing, wearing a mask, and isolation of potentially infected patients were effective in preventing the spread of respiratory virus infections. It is not surprising that methods of the included studies were at risk of bias as these types of interventions are difficult to blind, are often set up hurriedly in emergency situations, and funding is less secure than for profit making interventions. Hasty design of interventions to minimise public health emergencies, particularly the six included case-control studies, is understandable but not when no randomisation (not even of clusters) was done in the several unhurried cohort and before and after studies, despite randomisation leading to minimal disruption to service delivery. Inadequate reporting often made interpretation of before and after studies difficult.

The settings of the studies, carried out over four decades, were heterogeneous, ranging from suburban schools to military barracks, intensive care units, paediatric wards in industrialised countries, slums in developing countries,w1 and day care centres for children with special needs. Few attempts were made to obtain socioeconomic diversity by, for example, involving several schools in the evaluations of one programme. We identified few studies from developing countries where the most burden lies and where cheap interventions are needed. Even in Israel, the decrease in acute respiratory tract infections subsequent to school closure may have been related to atypical features: the high proportion of children in the population (34%) and limited access to over the counter drugs, which together with the national universal comprehensive health insurance means that symptomatic treatment is generally prescribed by doctors.

Compliance with interventions–especially educational programmes–was a problem for several studies, despite the importance of such low cost interventions. Routine long term implementation of some would be problematic–particularly maintaining strict hygiene and barrier routines for long periods, probably only feasible in highly motivated environments such as hospitals without the threat of an epidemic. (Jefferson et al., BMJ)

I give the authors credit for trying to ferret out as much information as they could from an impoverished scientific base. I fear they have slightly oversold their findings, although I fully appreciate the notion that in this case no harm is likely to result. The indicated measures are probably prudent even if we don’t have good information to know they work.

But we should face the fact we don’t really know more squarely. The Conclusion in the Abstract probably reflects the actual findings more accurately than their other statements:

Conclusion: Routine long term implementation of some physical measures to interrupt or reduce the spread of respiratory viruses might be difficult but many simple and low cost interventions could be useful in reducing the spread.

Yes, prolonged use of these methods would be difficult, and yes, they could be useful in reducing spread. But I think we knew this. What they added is there is precious little in the scientific literature to substantiate it although some of it might be suggestive. Unfortunately the paper came out sounding much more definite than warranted. Sigh.

Comments

  1. #1 Tom DVM
    November 29, 2007

    Two years ago when we discussed NPI’s…and they said they were pretty much useless…and they wouldn’t be needed because we had vaccines and antivirals, the ‘magic pill’ and the pandemic wasn’t going to kill as many as died of smoking each year anyway (3-5 million only worldwide).

    Now, everything is about NPI’s including quarantine which is a joke…they might want to worry more about how they are going to feed the masses and keep them from storming hospitals etc…

    …and again…where is the supportive therapy…do they have a plan for supplying antibiotics to, at the very least, every young child who requires it.

    Despite more than two years of discussion…scientists-regulators with the ‘real’ power to make a difference…still don’t have a ‘friggin’ clue.

  2. #2 herman
    November 29, 2007

    After reading my comic book, I learned that our new attorney general, and the head of the CDC have decided it is time to forget about quarantine of pandemic patients. They have discovered waterboarding not only prevents bird flu, but also cures those inflicted with the disease. And 35 doctors at the CDC have endorsed this conclusion, after learning they would be terminated if they did not sign the endorsement.
    The attorney general has announced that in the upcoming presidential election, all those who vote for Rudy Guliani will be excluded from the future preventive treatment for all US citizens. But all Democrats, all members of the US branch of the Communist Party, all those who have demonstrated against the Iraq War, all those have checked out subversive left wing books from the public library, all those who look like they may be terrorists, and all those who do not vote for Rudy Guliani for president, will receive mandatory preventive treatment for bird flu. This means all the CDC doctors who recently graduated from the United States Center for Training in Torture, will be assigned the task of going to your homes. Usually they will knock on your door at 3AM. They will strap you to a board, put a cloth over your face, and pour water in the cloth. In this way you will not ever become ill with bird flu. If you refuse the treatment, they all carry a machine gun.

  3. #3 Into the Woods
    November 29, 2007

    Herman – what a perfect solution, an almost final one.

    What happens when the common good is no longer part of the bottom line?

    The answer is touched on in the best throw-away line in the article:

    It is not surprising that methods of the included studies were at risk of bias as these types of interventions are difficult to blind, are often set up hurriedly in emergency situations, and funding is less secure than for profit making interventions.

    Scientists. Gotta love em.

    Here’s my runner-up:

    The researchers from Australia, Italy, the US and the UK warn that combining measures like hand-washing and rigorous use of masks, gloves and gowns could be the best, and indeed only, line of treatment.

    Sounds like the PPE/NPI team takes first place in a one-entrant tournament. Get out there and support your team.

  4. #4 herman
    November 29, 2007

    The British Government has failed to purchase enough masks for a possible flu pandemic, and many MPs demanded the masks be bought. France has an adequate supply. The US, under the leadership of the CDC, recommended hospitals use cheap 25 cent masks that are totally useless. Thank you CDC. This means many nurses and medical staff will not want to work, since they have inadequate protection. As far as quarantine, the UK government has already announced they will use the army to stop people from leaving the cities during a pandemic, and they have already identified buildings all over the country where cadavers can be stored. What the hell does the CDC plan to do with the dead bodies, bury them in your back yard?
    During the Spanish Flu Pandemic of 1918 volunteers would go up and down the streets in Philadelphia picking up the dead bodies with a horse and wagon. Citizens were instructed to place the bodies in the front yard. There were not enough caskets, and so mass graves were dug, and and the bodies were taged so you could identify the corpse later if you wanted to place it in a private grave.
    At one army base in Kansas, the commander of the base commited suicide. It appears he could not endure seeing so many of his troops die.
    If a pandemic hits the US, will the CDC order patients in hospitals be euthanised, as occured in New Orleans in a public hospital for the poor during Katrina? Of course no order was given, but patients were murdered. And across the
    street at a private hospital, all patients were evacuated.
    Will there be a special treatment, called euthanasia, for the poor who are sick, while others who have money, will receive adequate care? Since our government has legalized torture, what is wrong is they now legalize euthanasia for the poor during a pandemic? Since our beloved gestapo leaders kill for oil in Iraq, what is wrong with doing it in the US? Since the law is now whatever the president says it is, who is to stop him if he wants to legalize euthanasia for the poor during a pandemic?

  5. #5 Tasha
    November 29, 2007

    When they talk about masks being effective against the flu, is this what they mean?

    http://spewingforth.blogspot.com/2006/11/mask.html

  6. #6 herman
    November 29, 2007

    In regard to my above post, please note it is an attempt at black humor; since euthanasia of the poor, even by the insane standards of our government, is impossible and unacceptable. I am just trying to show how horrible it is to torture people, especially when it is your own government that does it.
    How can an attorney general say he does not know if waterboarding is torture? I have never seen anything so repulsive in my entire life.
    And of course our hospital staff should have the most advanced respirators during a pandemic; or otherwise they will not come to work. Where are those respirators. They do not exist.
    I apoligize in advance if anyone is shocked by my post.
    I was just trying to use humor to try and get your attention. The poor must receive the very best care our nation can provide during a pandemic.

  7. #7 M.Randolph Kruger
    November 29, 2007

    Herman you are full of shit. No one from the US government ordered anyone to be euthanized. I am sorry Revere for that particular burst but Herman is over the line.

    Herman, that is a direct statement of a deliberate wrong doing and here you are required to produce facts or something to back it up. Nothing to back it up at all. You got something to prove that other than some bullshit off the wall, third world lefty Micheal Moore website? Be careful. There are people who are reading this that could take action for statements against them and not only just you personally. There are laws against slander and libel. This here is the written word and I am sure that it is prohibited here.

    And for your information pal, hours before Katrina hit there were a total of about 20 FEMA people on the ground in Louisiana and Mississippi. Why cant you blame the woes of Katrina and a hurricane on 3.5 million who didnt get out of its way? You obviously have to blame it on 20 FEMA reps.

  8. #8 Mike
    November 29, 2007

    Revere: You’ve had a long-standing reluctance to accept that non-pharmaceutical interventions would do any good. And I agree your logic IS sound, statistical analysis and all. However, these methods DO have at least the potential for good, they are easily obtained and implemented by common folks, and they don’t cost much. Moreover, there’s no harm or downside to them that’s been shown to my knowledge. I do realize proper fit, proper training and consistent correct usage need to be considered. But prevention of disease and death of self and loved ones is a powerful motivator. At least allow for people to provide themselves some self-help.

    I think it’s instructive to present one comment from the UK study which you left out, with emphasis on the last comment.

    “What this study adds:

    Several physical barriers, especially handwashing, masks, and isolation of potentially infected people, were effective in preventing the spread of respiratory virus infections

    Such interventions should be better evaluated and given higher priority in preparation for pandemics.”

  9. #9 revere
    November 29, 2007

    Mike: I can understand why you feel I am reluctant to accept NPI as doing any good but in fact that is not my position. I am trying to call into question the attitude that we have to use them because we don’t have any other methods. Some NPIs are harmless or conceivably good for other reasons even if they did nothing for a pandemic (handwashing might be an example). When it comes to masks, however, I think we should be skeptical as they are not harmless. They could lead someone to take chances they would not otherwise take, they cost money (a lot of money, in the aggregate) and they are being marketed with claims and beliefs that might not be justified. By raising questions about NPIs I am trying to stimulate some debate and questioning, not introduce unwarranted and undue skepticism.

  10. #10 Tom DVM
    November 29, 2007

    “… I think we should be skeptical as they are not harmless. They could lead someone to take chances they would not otherwise take, they cost money (a lot of money, in the aggregate) and they are being marketed with claims and beliefs that might not be justified. By raising questions about NPIs I am trying to stimulate some debate and questioning, not introduce unwarranted and undue skepticism.”

    Influenza vaccines that remain unproven in the field and antivirals that have proven inadequate in the field and are off-label when suggested for indeterminate periods of time as preventatives…also amount to false-assurance.

    I think professionals acting with false-assurance from influenza vaccines and antivirals are far worse then the the limited use of NPI’s by the general public.

  11. #11 M. randolph Kruger
    November 29, 2007

    Its going to be a mill of try everything if it comes. Snake oil. There isnt enough of anything to do this. Me, I think we ought to stock up on food for the kids and put them in the houses under lock and key. Canada and the US, Germany, maybe France’s populations are all in the prime kill ages with massive older populations. All would fall in a generation as there is no one to pay the taxes, there is no one to support the much larger, older populations.

    We would lose a lot of older ones from starvation too. Pray that it never reaches even 5% because thats the prep level we are planning to build up to.

    I hear brake fluid and bleach might work….Nyah just kidding…

  12. #12 AnnieRN
    November 30, 2007

    Real life is never as cleanly defined as the perfect study, especially in public health. There are just way too many parameters that are beyond the control of anyone.
    Look at the worst-case scenario, and go from there. For me, I have to look at the real-life scenario of what happens in my home. What happens during the sneezing fit of my mentally- and physically-impaired 19-year-old son? It takes until sneeze #4 for him to turn his head into his sleeve, to catch the rest of his sneezes there. In the meantime, he’s sneezed all over everything and everywhere else. If it’s in the car, then the windows, dash, console, items in the console, me, his lap, etc. are all coated with secretions. God help us if that happens with pandemic flu. For me, I consider the use of a cheap, “ineffective” 25-cent mask, and tell myself, “Hmm. not a bad idea.” At least the mask could catch the mucous/wet secretions in the first sneeze, and the wet secretions in the masks can catch most of the rest. Heck, if people aren’t wiping blobs of mucus off their shoulders, you know that the mask caught something. I can afford a case of cheap masks.
    If we’re talking about slowing down a pandemic, I think we can be assured that after the general public understands how serious it truly is, they’re going to be grateful that my son isn’t sneezing big blobs of mucus on them. And that’s aside from the value of giving masks to people for the sheer– but unfortunate–value of helping them to do something simply to prevent panic–another horrible issue. Just my thoughts. AnnieRN

  13. #13 Grace RN
    November 30, 2007

    Odd, I have a feeling a similar discussion (sans internet) took place in 1918 and 1919.

    Layered NPI’s are logical, rapidly enforeceable, relatively cheap and proven to work (Philly vs St Louis).
    Let’s not miss the forest for the trees.