November 7th, 2022

Five Quick Questions from Our Course, “ID in Primary Care”

Examples of non-digital, non-electronic learning tools, for historical purposes only.

As noted on this site before, we put on a course called “ID in Primary Care” every year for clinicians doing truly the hardest job in medicine — frontline primary care. Why is their work so challenging? While we can focus on one field, infectious diseases, they have to be aware of everything.

Tough task indeed.

We’ve been holding our course virtually since 2020, so this is our third time with the online-only, live-streaming format. On the plus side, this has allowed a greater number of participants, saves a whole lot of money both for travel and the meeting venue, and certainly has a much smaller carbon footprint.

On the other hand, we miss the direct contact with those who attend. Plus, Zoom fatigue is a real thing, and we have zero idea if our jokes land.

Pros and cons of this approach aside, we still draw a great mix of internists, family practitioners, nurses, and PAs, and every year they ask us terrific questions about clinical problems that they encounter on a regular basis.

Here are a quick five:

Question #1:  I have a patient who says they get recurrent shingles several times a year, so she’s periodically back on valacyclovir. I can’t find anywhere how to manage this — boost their vaccine? Suppressive valacyclovir? If so, what dose? Help!

Answer: Ah, the patient with “recurrent zoster” — I put it in quotes because most of the time it’s actually not zoster at all. It’s either HSV (which can look strikingly similar) or a dermatologic manifestation of post-herpetic neuralgia, where someone has pruritus or discomfort in the same anatomic location of a zoster outbreak, so they scratch away and develop itchy red bumps.

When patients do get another case of zoster, it’s usually in a different dermatome, separated from the first episode by several years.

Have your patient stop the chronic antivirals if they’re on them, and next time they have an outbreak, get a swab and do a PCR for HSV and VZV on the lesions. If the diagnosis is still uncertain, have them check in with your favorite ID-oriented dermatologist if you’re lucky enough to work with one of these brilliant clinicians.

For more on this entity, read The Patient with “Recurrent Zoster”, which I have sent along to numerous eConsulters over the years.

Question #2:  My patient is about to start a TNF blocker for ulcerative colitis. She comes from a country that gives BCG vaccine to all children. Should she get both an IGRA and a tuberculin skin test to rule out latent TB? I worry about false positives with the BCG.

Answer: If your prior probability of latent TB is low, as it is for most U.S. citizens, then one test should suffice, and go with the interferon gamma release assay (IGRA). However, if the person is from a highly TB-endemic region, especially if they recently immigrated here, and are about to start these immunosuppressive medications that greatly amplify the risk of TB reactivation, then the guidelines say to consider doing both — and this is what we would recommend. If either test is positive, I would give preventive therapy before starting the anti-TNF agent.

And no, prior BCG should not dissuade you from this strategy. As some regions where this vaccine is administered have very high rates of TB, there is no way to distinguish positive skin tests from BCG (which fade over time), versus from latent TB, versus both — and the vaccine doesn’t work that well in adults anyway.

For more, check out these terrific online resources:

BCG and false-positive tuberculin skin tests

Online TST/IGRA interpreter

BCG world atlas

Question #3:  My patient has recurrent UTIs, but she is older with chronic renal disease. What’s the real story on use of nitrofurantoin in this setting?

Answer:  Nitrofurantoin has made an amazing comeback in UTI treatment over the years, largely due to rising rates of community resistance to other agents and concerns about fluoroquinolone toxicity. However, it has poor tissue penetration, and prescribing information has long said not to use at CrCl <60 ml/min because of insufficient renal excretion and accumulation of the drug leading to more toxicity — in particular that nasty pulmonary hypersensitivity syndrome.

By contrast, in a 2015 review by the American Geriatrics Society, the conclusion was that nitrofurantoin could be safely used down to an estimated GFR of 30, provided the treatment course was 7 days or shorter.

Helpful to know this if other options are limited.

Question #4:  I know that the pneumococcal vaccine recommendations have been updated, but it’s so confusing what to do with so many options. Any simple way of addressing this, in particular for those patients who’ve been vaccinated before?

Answer: We’re most definitely in a transition phase when it comes to pneumococcal vaccination, driven by the availability of the two new conjugate vaccines, especially the 20-valent one. Sometime in the near future, everyone getting a pneumococcal vaccine will get the pneumococcal 20-valent conjugate vaccine (PCV-20), and be done. Hooray!

But until then, we have a whole slew of people who’ve received older vaccines, both the conjugate (PCV13) and the polysaccharide versions (PPSV23). What should we do with them now?

My colleague Dr. Mary Montgomery put together this handy slide for her talk on adult immunizations, which I am sharing with her permission:

Question #5:  Is the pandemic over?

Well it’s not over — but it sure has changed.

Want evidence? Just imagine this video appearing a year ago — inconceivable.

Today? It was a big hit on SNL this past weekend.

Suspect that for some, it’s too soon, while for others, it’s perfectly timed satire.

For me, it’s both. How about you?

8 Responses to “Five Quick Questions from Our Course, “ID in Primary Care””

  1. roberta carroll says:

    Any suggestions about further Pneumococcal vaccination in geriatric (>75-80) patients who have had PPSV23 at age 65 and PCV13 subsequently, but no boosters since?

    • Mary Montgomery says:

      The good news is that no further vaccinations are needed! They are fully vaccinated if they have already had PPSV23 and PCV13.

  2. Ian Miskin says:

    There is a small number of rare birds- board certified family practitioners who are also specialists in infectious diseases.
    As you mentioned- primary care ID is a different kettle of fish from hospital-based ID.
    Maybe we should be encouraging these birds to procreate as the optimal and ongoing answer for questions such as those posted?

  3. Jules says:

    Hooray for pcv20!

  4. John Mosby, MD says:

    Both my Nephrologist and Internist, as well as a local pharmacist, think that PPSV23 boosters are needed every 5 years. I have shown them both the CDC charts indicating otherwise, but the wording seems to mislead them. I’m over 65 and received the pre- and post- 65 yo doses, and have steadfastly refused to accept another. I’m happy to see my interpretation of the recommendations for that vaccine confirmed here!


    jj0 years old with a positive intradermal test year after year until a Health Department Nurse told him to stop—once positive, always positive. Now, at least 55 years later, he wants to know whether to get either the Prevnar 13 or the the Prevnar 20. What should I tell him?


    Hard to type with a twitchy keyboard on an Ipad.

  7. Emily Cartwright says:

    What pneumonia vaccine should we be giving to an immunocompromised person who has had the PCV13 and the PPSV23 and is now due for a PPSV23 booster?

HIV Information: Author Paul Sax, M.D.

Paul E. Sax, MD

Contributing Editor

NEJM Journal Watch
Infectious Diseases

Biography | Disclosures | Summaries

Learn more about HIV and ID Observations.