December 4th, 2016

Just Wondering: Quick ID/HIV Questions to Ponder During Month Number 12

A selection of ID/HIV questions that have been dogging me over the past year, some longer:

  • Why is there no reliable, readily available PCR diagnostic test for malaria? Seems especially ironic since the one for babesia has become so commonly used. Does the Binax antigen test make it unnecessary?
  • Why aren’t we actively recommending Zika testing for couples who return from endemic areas and are interested in conceiving? A negative test would make a low-likelihood but serious outcome (congenital Zika) even less likely. They could still wait the recommended six months if they want.
  • What is the right abbreviation for Pneumocystis pneumonia?  Is it “PCP” (PneumoCystis pneumonia) or “PJP” (Pneumocystis jirovecii pneumonia)? Have heard smart people use both; I prefer the former.
  • Once there are more manufacturers of generic daptomycin and the price drops, how long before it’s used more than vancomycin? If we never have to monitor vancomycin levels again, there should be a small celebration.
  • In the big new HIV vaccine study just starting, how many participants will also be receiving PrEP? Here’s the study design of HVTN 702, and PrEP clearly is allowed. I suspect it won’t be available to most of the participants, otherwise it could make it hard to discern whether the vaccine actually works.
  • Does anyone really know the full meningococcal vaccination recommendations without looking them up? For the 99% of us who don’t, here they are. This is an old bugaboo, inspired by the new recommendation to give meningococcal immunization to all HIV patients.
  • Could the headlines be any more misleading about how many patients contracted HIV or HCV from the dentist who used his own equipment? Here’s an example — you have to read it carefully to make sure you see the “May” in there. But gotta sell papers/get clicks (and I just contributed to the latter).
  • drones-to-shoot-mm-vaccineSpeaking of, is this the headline of the year? I think we have a winner, folks — “GOVERNMENT DRONES WILL SHOOT VACCINATED M&MS AT PRAIRIE DOGS.” The disease, for the record, is the “sylvatic plague.” You have to read the full story to believe it. And just wait for the anti-vaxxers to protest.
  • If primary care clinicians had a rapid diagnostic test that could tell patients definitively that they had a specific viral respiratory tract infection, would this decrease the use of outpatient antibiotics? They could say, “Mr. Smith, your test came back, and you have rhinovirus.” I say “Yes it will”; my colleague Jeff Linder (a primary care internist who studies antibiotic overuse) is skeptical.
  • Will broadly neutralizing antibodies (“bNAbs”) ever have a role in HIV treatment? Not based on this study. Admittedly it’s early in bNAb research, but to date I’m not getting the bNAb enthusiasm.
  • We have penicillin G, and penicillin V, but what about the other letters? Hat tip to John Cafardi for this one.
  • Wouldn’t it be useful if ID doctors had some formal training in wound management? Big gap for many (most?) of us.
  • What percentage of non-occupational HIV post-exposure prophylaxis courses are unnecessary? I’m estimating 99.9994%, but that train seems to have left the station, with no going back.
  • mytesi3Why did the new makers of crofelemer change the name from (the absurdly wonderful) Fulyzaq to (the less remarkable) Mytesi? And here’s an artist’s rendition of a Mytesi, in case you were sad about the extinction of Fulyzaq.
  • In Lyme-endemic areas, why is there no recommendation to give a single dose of antibiotics to children with tick bites? Odd that we use this strategy in essentially all adults, and almost no children — it’s as if we were applying drinking-age criteria to this completely unrelated issue.
  • Why is a CSF exam recommended in all patients with optic or otic syphilis? Treatment is the same (IV penicillin) regardless of the results. Have been asking this question for years.
  • What fraction of HIV viral load tests that come back “VIRAL RNA DETECTED BUT BELOW THE QUANTIFIABLE RANGE OF THE ASSAY” are clinically important? Boy that must be rare. The ratio of (Emotionally important to patient)/(Clinically important to patient) must be nearly infinite.
  • What’s it like to have an oral carbapenem? Someone from Japan might know.

Ok, time for a couple of quick non-ID ones:

  • When will the Washington Redskins change their offensive name? Or the Cleveland Indians get rid of their unfunny mascot?retire-chief-wah
  • When will the torture of choosing a password be replaced by something easier and more reliable? Here’s one recent example. Arrghh.


Hey, it’s National Influenza Vaccination Week! Check your party schedule carefully.

It's National Influenza Vaccination Week (NIVW)! Did you know that flu season can begin as early as October, it usually peaks between December and February, and it can last as late as May? As long as flu virsues are spreading, it's not too late to get a flu vaccine to protect yourself and your loved ones through fall, winter and into spring. #GetAFluVax

9 Responses to “Just Wondering: Quick ID/HIV Questions to Ponder During Month Number 12”

  1. Jon Blum says:

    Regarding doing LPs in ocular syphilis, Khalil Ghanem (a very thoughtful syphilis expert) gave his answer to that question at ID Week. Here’s what I wrote down:

    “Most ocular syphilis patients have a positive serology, but it can be RPR negative. 30% of ocular syphilis patients have a normal CSF, so CSF is not used to rule out ocular syphilis. So why do an LP at all?
    1. To clinch an uncertain diagnosis, if the CSF VDRL comes back positive.
    2. Baseline CSF to follow with repeat exams.
    3. Objective measure in patient with fluctuating course. These patients often have a stuttering course so this can be useful.
    DO NOT DELAY RX to get the LP, because they can (not commonly) progress to blindness in <1 day."

    In case #3 is not clear, his point was that some of these patients will not improve linearly, and that makes everybody worry about treatment failure. In those patients, an LP provides objective evidence of response.

    • Paul Sax says:

      Thanks Jon! To which I would reply (based obviously on less experience):

      1) Diagnosis is usually clear BEFORE the CSF exam.
      2) What data show that following CSF with repeat exams is useful in improving response to ocular syphilis?
      3) The CSF activity in ocular syphilis correlates imperfectly with the clinical disease in the eye, right?

      I’m sure there are isolated cases when the CSF exam is useful, but my point is that in most of them, it’s just another data point that doesn’t change therapy.


      • Jon Blum says:

        I suspect most of the time, the CSF has not so much impact on therapy. Assuming the dx is already clear, how often is it helpful in F/U? Indeed, while guidelines recommend follow-up LPs in “regular” neurosyphilis, I think there is some doubt as to their value if the RPR is improving (see Marra CM et al. 2008, CID 47: 893). In my vast experience with two (!) ocular syphilis patients … you get my point, I am not an expert to address this question, I was just repeating what I heard. Perhaps Dr. Ghanem or Christine Marra would be able to comment on this topic with more authority.

  2. tom benzoni says:

    To riff on your password issue:
    We are creating an illusion of safety by those rules.
    They are based on “War Games” (1983) model of hacking.
    Modern day hacking is done by computers, not some teenager in Gdansk.
    Put “xkcd” and “936” into your search engine for a good if geeky lesson on passwords.

  3. Joel Gallant says:

    PCP vs. PJP? PCP wins hands down. First, we were given permission to keep the original abbreviation by the microbiology nerds who changed the name of the organism. They wrote “Changing the organism’s name does not preclude the use of the acronym PCP because it can be read “PneumoCystis Pneumonia.” (Stringer JR, et al. Emerging Infectious Diseases 2002;8:891-6.)

    More importantly, the original abbreviation is laden with historical and emotional significance. The difference in the use of the two abbreviations may be somewhat generational, with the original “PCP” being retained by those of us old enough to have taken care of dying patients during the dark days of the AIDS era. Call me old fashioned, but changing the abbreviation now seems unnecessary, pedantic, and maybe even disrespectful.

  4. Jeannot Dumaresq says:

    Hi Paul!

    Concerning your question #1, there is now a good commercial NAAT pour malaria:

    For question #9, here’s a study showing that sadly it doesn’t really prevent physicians from overprescribing antibiotics (initially yes, but not in the following days):

    • Paul Sax says:

      Thanks, Jeannot. I don’t think the malaria PCR assay you cite is available in the USA (but I could be wrong).


  5. I need someone to explain to me how this disease became so prominent in the black community. Suddenly all diseases effect black people the most and this doctor did not give a good explanation as to why.

HIV Information: Author Paul Sax, M.D.

Paul E. Sax, MD

Contributing Editor

NEJM Journal Watch
Infectious Diseases

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