Now we can add a fourth case this year of avian flu in a human residing in the US, again a mild case with conjunctivitis in an individual in close contact with infected dairy cows. No surprise there, but I'm waiting to see what happens with all the summer state fairs that provide more opportunities for human exposure to infected poultry and mammals.
Summer Covid Watching
The bottom line in the US is that covid infections are likely still pretty low, and we don't really know if we'll see a significant surge in the next few months. Any prediction is harder these days because our monitoring systems are probably the worst they've been in the past 4 years. On a national public health level, post-pandemic reporting and tracking have been relaxed and made voluntary, which for many healthcare institutions and jurisdictions can mean no reporting at all. On an individual level, people are less likely to seek testing or treatment, probably due to a combination of numbness from years of being on the edge plus relatively lower disease severity.
I'm focusing on a few data sites.
First is the CDC's Respiratory Virus Weekly Snapshot. The percentage of positive tests sheds some light in disease activity, still cloaked in individual behaviors in seeking testing in the first place and lack of reporting from most home testing. The recent covid percentage is trending up, though not at the level of fall 2022.
Covid wastewater trending is helpful and perhaps the least altered by changes in practice over time. Unfortunately, vast areas of the country have no reporting. Activity levels are rising particularly in the western US, but still well below prior surges. I noted that wastewater updating took a holiday last week, so we're missing the most recent numbers.
Second, I'm keeping a watch on relative predominance of different variants, with an eye to how effective our next vaccines will be. The top 4 variants currently are KP.3, KP.2, LB.1, and KP.1.1. Any late summer or fall surge likely would include one or more of these. I'm waiting for more data on how well serum from recipients of the new vaccines will neutralize these variants in vitro.
Should I Change My Annual NJ Beach Trip?
A flurry of beach closings due to poor water quality last week. I couldn't find any national consortium on this, so you'll need to look at specific states to find out what's going on at your beach rental house this summer. In my browsing I particularly liked the Massachusetts interactive water quality dashboard; Massachusetts seems to be one of the harder-hit states.
The song I Ain't Worried was written for the beach football scene in the movie Top Gun: Maverick. It was conceived early in the pandemic (when we were worried!) and was an upbeat breather contrasting with the intensity in the rest of the movie. Not a bad antidote for your summer worries, whatever they may be.
Not only did the summer solstice arrive June 20 as expected, the temperatures outside confirm that summer is here. I noted 100 F in the shade on my patio Saturday afternoon.
Summer usually means a switch in circulating pathogens and pediatric infections. Outdoor activities mean more scrapes and scratches which then means more cases of cellulitis, abscess, and osteomyelitis. Also in the mix are the vector-borne infections including Zika, Powassan, and West Nile viruses, babesiosis, Lyme disease, Rocky Mountain spotted fever, and yes, even in the US, malaria and dengue. International travel lengthens the list considerably.
Respiratory viruses usually take time off in the summer, other than enteroviruses - the name misleads many to conclude these are primarily GI pathogens, but in fact they are more likely to cause mild respiratory illnesses. They do replicate in enterocytes and the viruses are found in stool, hence the name. Peak enteroviral season usually is August and September, though they are present year-round.
That said, let's look at a few out-of-the-ordinary pathogens to watch for this summer.
Summer Covid?
Yes, I know I'm repeating myself, but it's again worth noting that our ability to monitor SARS-CoV-2 is in a new era. With the pandemic ended and little to no availability of free testing, plus local, state, and federal jurisdictions relaxing reporting requirements, we're mostly down to crystal ball guidance to know when to expect the next surge. The closest to an accurate predictor is waste water monitoring, though it too is limited. Here's the latest:
You can see the start of an upward blip maybe - looks a lot like last year when we had a mini-surge that peaked in September and seemed to correlate with clinical disease. Levels are low now. Test positivity is up a little out west.
CDC's Advisory Council on Immunization Practices meets this week, June 26-28, with covid vaccines discussed Thursday morning and voted on Thursday afternoon.
Summer Bird Flu?
Still not a major worry for us, other than folks who have contact with live poultry (included backyard coops), other livestock, and unpasteurized dairy products. Still, it's good to have a plan for when and how to evaluate potential cases if they show up on your doorstep.
If you are seeing a child with a cold this summer (remember, so far the 3 cases of AH5N1 in the US have been mild and include conjunctivitis), please add in a few questions: any exposure to livestock, or to others with this exposure - this includes those state fairs with petting opportunities; also ask about unpasteurized dairy ingestion. If the answer is affirmative, this is someone worth testing for influenza, and if positive for influenza A in the summer in the US should launch more investigation that will involve your local health department.
Fortunately, CDC has lots of helpful advice at the Bird Flu web site. Scroll down to the Recommendations for Clinicians. The weekly update doesn't contain significant new actionable information. Other pages are in the process of being updated, but again your local friendly ID doctor or local health department are good partners to help you.
Summer Reading?
Not a summer pathogen, but will be occupying some of my time the next few months. Many of you probably would surmise that Dr. Fauci's new book is high on my list, but in fact it's not. I lived through all of this, plus I'm much more interested in the science than the politics. I'm sure it will be a bestseller, and I'm appalled at the ongoing vilification and threats he's experienced.
My biggest summer reading project is Emily Wilson's new translation of The Iliad, but it's not really a beach book in spite of the seas and beaches mentioned in the epic. For my annual beach trip I'll instead be buried in noir mysteries and other enjoyable light reading.
Romare Bearden's Odysseus Enters at the Door Disguised as an Old Man, c. 1977, from https://www.nga.gov/learn/teachers/teaching-packets/bearden.html.
Bird flu has been in the headlines, accompanied by the usual extremes of concern levels. The past few weeks reminded me of Alfred Hitchcock's 1963 movie "The Birds," especially a diner scene where an elderly (my age?) amateur ornithologist (Ethel Griffies as Mrs. Bundy) attempts to explain why the "brain pan" size of a crow or blackbird makes any organized attack on humans impossible. The discussion is interrupted by another customer declaring the end of the world, interspersed with background shouts of orders for blood marys and fried chicken with baked potatoes.
Before we get to bird, a few other items of note.
Dengue Update
Maybe things aren't quite as bad, with a downward trend now apparent in the Americas.
The bulk of this atypical seasonality increase is from the Andean and Southern Cone regions of South America. Brazil by far leads the way, and Argentina, Peru, and Paraguay are in a second tier by numbers of cases. Here's a numbers breakdown for last week and for the calendar year as a whole:
Don't Dismiss Covid
Yes, the current variants and immunity levels in the US seem to result mostly in mild disease and numbers continue to trend downward, but we are seeing well over a thousand deaths per month from covid in the US. It is still a devastating disease.
No outbreaks in new jurisdictions in the US in the past week; Illinois and Florida still account for most of the cases this calendar year.
Highly Pathogenic Avian Influenza (HPAI)
The name itself is pretty ominous, cue those eery bird sounds from the movie. The biggest event last week was the confirmation of a case of influenza A H5N1 infection in a man from Texas, almost certainly acquired from the dairy cows he worked with. He was treated with oseltamivir and apparently is doing well. CDC issued a health advisory through their Health Alert Network last week, including a lot of good advice and helpful links. People who are around birds or dairy animals should take care; this includes those with backyard chicken flocks. The public health messaging has been pretty consistent: no cause for alarm, and certainly no reason to avoid dairy products or eggs at your local store (assuming the dairy products are pasteurized). FDA has a great Q&A page on this.
Note however that we have pockets of these viruses throughout the US, including in wild mammals.
We can be reassured that all of these strains are being tracked and sequenced worldwide through the Global Influenza Surveillance & Response System (GSAID). Scroll down at that link to watch an animation of the geographic spread of influenza A H5Nx viruses worldwide over the past few decades.
We have several antiviral therapies available, and vaccine prototypes are ready to enter mass production if necessary. So far, none of these strains seem well adapted for human-to-human spread, but if that happened it would be a major event that would cause much more concern. I'm also watching to see if this appears in pig populations, since swine flu viruses have been seen in the past to foreshadow human spread. Pigs have similar flu viral receptors to humans, so spread in pigs can be seen prior to a jump to humans. Thankfully, many of the events that facilitate spread among different animal species also are associated with lower virulence, so clinical impact is minimal.
Don't Look Up (Without Your Eclipse Glasses)
Yes, I know it's yet another movie. Just be careful with tomorrow's eclipse.
It's Easter time, when my thoughts turn to chocolate bunnies. Not only do they taste better than real bunnies (well, to think of it, I may have never tested a real bunny), but I have been unable to find any reports of tularemia transmitted from chocolate bunnies.
Although we are clearly beyond the peak of winter respiratory infection season, we still have plenty to think about from last week.
Covid Household Transmission From Asymptomatic Children
A prospective study showed a high secondary attack rate (SAR) for covid in households likely stemming from asymptomatically infected children. The study was well designed to try to answer this question, identifying asymptomatic children in Canada and the US who were tested for SARS-CoV-2 for either non-household contact with a known covid case or as part of routine hospital screening. The study covered a 15-month period, and results were analyzed according to viral variants predominating in the community at those times: 1/31/21 - 6/30/21 was predominantly alpha or mixed variants, 7/121 - 12/19/21 was delta, and 12/21/21 - 4/22/22 was omicron. The authors compared household SAR of SARS-CoV-2 positive children to rates of those who tested negative. There are many nuances to the study, but here's the bottom line:
SARs were higher with younger index cases (< 5yo versus 13 - <18 yo), if the index case eventually developed covid symptoms (versus continuing asymptomatic), and during delta and omicron time periods versus the interval when alpha/other variants predominated. If you have access to the full text of the article, skim the Methods section to get an idea of the tremendous amount of effort involved in collecting this kind of data.
Dengue in Puerto Rico
This past week Puerto Rico health authorities declared a public health emergency due to dengue, the first time this has happened in the territory since 2012. What I'm sure is alarming to those authorities, beyond the sheer number of cases (524) in 2024 so far, is that this isn't peak dengue season. As befitting the mosquito vector, cases tend to rise in the summer when it is wetter. See below, with my apologies for lack of English translation. You can click on the Week 10 report in the PR DOH Arboviral Diseases Weekly Report for the full document.
In other words, the worst may be yet to come. (The dashed red line is the epidemic threshold which is higher in summer/early fall weeks; August usually is the peak month for rain in Puerto Rico.) We can certainly expect cases in the mainland US, including in non-travelers living in Florida and other states that have experienced autochthonous dengue cases in the past.
Meningococcal Group Y Alert
CDC issued another HAN report about increasing cases of invasive meningococcal disease due to group Y, a phenomenon that has been noticed for a couple years now.
Note that the incidence rate is very low; this represents a relatively small number of cases but still quite significant given the severity of meningococcal disease. Now is a good time for frontline healthcare providers to read up about meningococcal disease in general including indications for vaccination and identification of high risk groups, especially for this outbreak: age 30-60 years, Black or African-American descent, and living with HIV; as well as the usual risk factors of close contact with a case, people at the age extremes, certain immunodeficiency diseases such as complement deficiencies, and some college settings. The HAN notice includes many useful links.
How's Your Ventilation?
CDC issued revised guidelines for indoor ventilation to help prevent respiratory virus transmission, including SARS-CoV-2. Take a look and maybe ask your friendly office landlord how your building stacks up.
Apparently I've missed it for a couple years, but CDC also has an interactive tool to see how changes in ventilation may improve viral particle clearance. I disappeared down that rabbit hole playing with it for about half an hour. Note the disclaimer at the top of the web page about some information needing updates, though I think it mostly concerns the old 6-feet social distancing and other recommendations rather than the tool itself. Here are results from a home with intermittent HVAC operation, uncertain filter rating, and running the HVAC system for 1 hour after a 4-hour period of gathering. Better results can be achieved with continuous HVAC operation (i.e. keep it on continuously during times of high occupancy), high MERV-rated (Minimal Efficiency Reporting Value) filter, use of HEPA (High Efficiency Particulate Air) cleaner, and other factors.
However, before you overhaul your home system or threaten your office landlord, note what this is really saying. The outcomes pertain to effectiveness of particle reduction in the air, which is different from measuring whether it lessens transmission of SARS-CoV-2, influenza, RSV, or other viruses. It makes sense that there would be some correlation, but until someone does a more definitive study comparing systems and actual viral infection rates, we don't really know to what degree ventilation efficiency changes infectious disease outcomes. Compare this with the study of secondary household transmission mentioned at the top today's post - a more difficult study design with results more directly related to clinical outcomes than just a study of airborne particles in a laboratory chamber. And, parenthetically, the household transmission study did not include individual home ventilation as a factor, so even those results are incomplete. This is complicated!
Measles Update
Measles marches on in the US and across the world. US cases continue to grow, now at 97 since January 1, fed in large part recently by outbreaks in Chicago: 21 new cases in the past week just in Chicago alone. Here are the latest US numbers and distribution from CDC:
In Search of Easter Candy
Once again my wife and I have used our granddaughter as an excuse to buy Easter candy. She's a picky eater, now the only chocolate bunny she will touch must be dark chocolate without any added flavorings or other adulterations. I applaud her good taste, but perhaps next year I'll do this shopping more than a few days prior to Easter Sunday. I had no trouble finding a multitude of milk chocolate bunnies, some with various additives including peanut butter, salted and unsalted caramel, marshmallow, and other ingredients that I might have considered inedible if presented separately from chocolate. Plain dark chocolate bunnies apparently are almost extinct, definitely at least a critically endangered species.
I should have kept track of my steps and car odometer for this year's chocolate bunny safari, though I doubt even the thousands of steps I tallied will offset my Easter candy ingestion.
Those words written by a famous children's author in 1988 remain relevant today; details to follow after a few mentions of other pediatric infectious disease news from the past week.
Covid Serology Update
The Infectious Disease Society of American updated their guidelines for use of covid serology testing. It is the 4th update since the pandemic began, but there isn't much new here. Currently over 95% of the US population has evidence of immunity either from natural infection, vaccination, or both. Serologic testing of individuals mostly is discouraged because it won't provide any useful clinical information to manage an individual's situation. About the only use might be to check immunity in immunocompromised individuals to help decide if immunotherapy could be warranted for prophylaxis or for treatment of active infection.
Covid in Young Infants
Early in the pandemic, most very young infants diagnosed with SARS-CoV-2 infection were hospitalized. This was due to a combination of the usual practice for febrile infants less than 1 month of age as well as the uncertainty of infection outcomes in this age group. I recall from my clinical experiences that it appeared that most young infants actually did well, though there were exceptions. Finally we have a study that gives us some more detailed data about young infants early in the pandemic. It is a secondary analysis of a prospective global study that recruited children presenting to pediatric emergency departments with illness and tested for covid. The study design allows for much more detail (and presumably more validity) than the other designs such as review of administrative data. The study (actually 2 studies combined) enrolled between March 2020 and February 2022. They ended up with 432 children testing positive for covid to compare with 616 testing negative. Clinical outcomes were generally more severe in the SARS-CoV-2-negative infants:
So, at least early in the pandemic, young infants with SARS-CoV-2 infection fared pretty well.
A Colorful Variant Update
Nothing new about this, but I admit to a strange attraction to colorful covid variant charts. I thought it was interesting to look back to see how the JN.1 variant progressed in the US.
The JN.1 shade of purple has been called "indigo purple" (hex #660999).
Varicella Misdiagnosis
A new CDC report suggests clinicians aren't too skilled in diagnosing varicella infections, perhaps because it is now much less common due to effective vaccination. The Minnesota Department of Health looked at suspected varicella cases from 2016 to 2023, a time when they implemented a new system for processing PCR testing of lesions. Of 208 suspected varicella cases, only 45% had positive tests; in vaccinated patients, the number dropped to 22%. They attributed this to unreliability of clinical diagnosis of varicella, especially in vaccinated patients, but I suspect other factors (improper specimen collection technique, testing unlikely varicella patients "just to be sure") may be contributory as well. Anecdotally I've certainly noticed how difficult the diagnosis varicella-zoster virus infection can be for younger clinicians who don't have the experience of seeing multiple cases in the pre-vaccine era.
Speaking of Misdiagnosis ...
I'm in my broken record mode again here. In case you've been hibernating or torporing, we're in the midst of a global measles surge. I read with alarm of a measles vaccine shortage in Canada. There are no signs of a similar shortage in the US; you can always check on US vaccine shortages at this CDC site. With spring break upon us now, and summer travels coming up, all of us need to brush up on measles diagnosis. Thankfully we have a lot of help.
Last Sunday, the CDC issued a Health Alert Network post with a number of useful links. The American Academy of Pediatrics provides a one-pager with great advice as well as a 5-minute video. Another source I've found very useful for years is from a now out-of-print textbook, Krugman's Infectious Diseases of Children. When I discovered libraries no longer carried it, I tracked down a used copy of the 10th edition (1998) released by a university library and have made continued good use of their black and white diagrams. Here's the clinical progression of illness, the key highlight here is the prodrome of a few days before the rash appears. This is very helpful in suspecting a measles diagnosis because the prolonged prodrome is very unusual in pediatric infectious exanthems.
Also useful is the development and distribution of the rash:
I failed to find a current global measles map so return to the CDC website to at least give a current view of US measles cases. For this calendar year we are now up to 64 cases spread over 17 jurisdictions.
Many clinicians may not remember that, though the first measles vaccine was approved for use in the US in 1961, it wasn't until 30 years later that a second dose was recommended. That was spurred by cases in the late 1980s appearing in vaccinated school children, the first major sign that a single dose wasn't sufficient to prevent outbreaks. That second dose was first recommended for 11-12 year olds by the AAP, subsequently dropped to the 4-6 year age group in 1997 to come into agreement with the CDC. Importantly, the interval between the 2 doses can be as short as 28 days for MMR and 90 days for MMRV vaccines, and early vaccination down to 6 months of age is indicated in special circumstances, such as for children who will be traveling internationally. Frontline pediatric providers need to be proactive in alerting parents planning international travel to ensure that their children ages 6 months and older are protected. Scroll down to the Special Situations section on the CDC immunization schedule notes.
Roald Dahl
I learned just recently that this famed children's book author lost a daughter to measles in 1962. He wrote 25 years later, "Olivia, my eldest daughter, caught measles when she was seven years old. As the illness took its usual course I can remember reading to her often in bed and not feeling particularly alarmed about it. Then one morning, when she was well on the road to recovery, I was sitting on her bed showing her how to fashion little animals out of coloured pipe-cleaners, and when it came to her turn to make one herself, I noticed that her fingers and her mind were not working together and she couldn’t do anything. 'Are you feeling all right?' I asked her. 'I feel all sleepy,' she said. In an hour, she was unconscious. In twelve hours she was dead.”
She had developed measles encephalitis. He wrote this in the late 1980s to encourage parents in the United Kingdom to accept a new MMR vaccine for their children (monovalent measles vaccine had been introduced in 1968 in the UK). He also wrote, “In my opinion parents who now refuse to have their children immunised are putting the lives of those children at risk. In America, where measles immunisation is compulsory, measles, like smallpox, has been virtually wiped out. Here in Britain, because so many parents refuse, either out of obstinacy or ignorance or fear, to allow their children to be immunised, we still have a hundred thousand cases of measles every year.”
Much has been written about Dahl's dark side (e.g. "an equal-opportunity bigot"), but I give him credit for trying to help children and their parents avoid the misfortune he and his family experienced.
