pertussis

It's been an eventful week for me but relatively quiet in the world of infectious diseases. I've just returned from a week's trek in the semi-wilds of Colorado. You may recall that last week's post included a mention of mosquitoes and high altitudes, noting that climate warming has been accompanied by trends of more mosquitoes at those upper elevation. I'm happy to report that after spending the week in the great outdoors at 5000 - 10,000 feet I only had a few bites and didn't even touch my insect repellent.

Turning skyward, I was able to view the September 17 partial lunar eclipse from Mesa Verde National Park; sadly my antique cell phone camera was unable to capture it. This morning I consulted my trusted 2024 print edition of The Old Farmer's Almanac to remind myself of the difference between an equinox and a solstice. The earth's axis is tilted at 23.5 degrees from the perpendicular as it revolves around the sun, and the equinoxes occur when both northern and southern hemispheres equally face the sun. Northern hemisphere solstices occur when the North Pole is most tilted towards (winter) or away (summer) from the sun. I learned so much this week!

Whooping cough was in the news recently, though really this is just a return to "normal" after the pandemic years. Here's the long view from CDC data.

On a more recent view, you can see the age breakdown.

I was involved in pertussis immunology and vaccine research very briefly in my career. I always like to mention an oldie-but-goodie article from 1992 showing that about one-quarter of UCLA college students with cough lasting longer than 5 days showed evidence of recent pertussis infection. It's a good reminder that pertussis in adults usually looks very different, and milder, than the classical whooping cough in infants. Diagnosis is difficult unless you think about pertussis as a possbility.

Maybe not so coincidentally with these news reports, the FDA VRBPAC meeting last Friday focused on using Controlled Human Infection Models (CHIMs) to try to develop a better pertussis vaccine. Yes, that's right, intentional infection of human volunteers to study various aspects of the disease. We need more information to improve pertussis control, given that our current acellular vaccines are less effective (but also with less side effects) than the predecessor whole cell vaccines. Large scale trials are difficult, expensive, and largely impractical in the present era, so it's time for new approaches. A group at the University of Southhampton in the UK presented some preliminary data from a CHIMs trial and also had a nice graph to put into perspective relative mortalities and contagiousness of pertussis compared to other pathogens:

The study itself was just a challenge study of human volunteers to determine the dose of organisms and the immunologic responses surrounding infection and colonization. It seems likely that these types of studies will be utilized more frequently in the future to improve our understanding of pertussis prevention.

Needless to say, I didn't join this meeting live, I was off the grid in Colorado, but I did skim through the recording and slides today. This wasn't a typical VRBPAC meeting where voting occurred, it was more of a discussion to guide future research.

More Wastewater

Speaking of returning to pre-pandemic levels of infection, I've been watching wastewater trends for enterovirus D68. You may recall that this was an enterovirus strain that figured prominently, but not exclusively, in outbreaks of acute flaccid myelitis that tended to occur in even-numbered years - pretty strange.

As you can see, the pandemic really ended this pattern, and nothing new is going on so far this year. However, wastewater numbers, at least for EV D68, have looked very different.

Will we see a blip upwards in AFM cases this year? I hope not.

More Colorado Learning

My landscape designer wife clued me in to the details of the quaking aspens, so named due to the fluttering of the leaves that have their own distinct sound. They are beautiful, both my wife and I wished we had better pictures to show you.

On another note, although I love to learn, one new factoid I happened upon was perhaps less exciting. Hiking at these altitudes, I learned that I'm not as young as I used to be!

Little known (and generally worthless) fact: I sold beer at Super Bowl VIII. However, it is with increasing guilt pangs that I plan to tune in to tonight's Super Bowl LVII game almost half a century later. The National Football League's highly discriminatory business practices and the medical risks to players color my appreciation of the game itself. From the medical perspective, of course it's the numerous instances of trauma more commonly involving the musculoskeletal system and brain that stand out; this year we've seen what was likely a rare instance of commotio cordis as well. Not to be overlooked, infectious diseases also have played a small role in the NFL, including an outbreak of MRSA on the then St. Louis Rams team. More on that later.

I'm happy to report nothing noteworthy in the past week's epidemiology of winter respiratory viruses, so I'll forego the usual graphs this week.

Promising New Therapy for Covid-19

Pegylated interferon lambda given as a single subcutaneous injection appears to be an effective new treatment for early covid 19 illness, according to results of a phase 3 trial published last week. About 1000 subjects received the treatment drug with an equal number receiving placebo. Subjects were at least 18 years of age, outpatients, and within 7 days of symptom onset. Most had at least 1 high risk criterion for disease progression. Eighty-three percent of the subjects were vaccinated, and the study spanned multiple variants including omicron. The active drug recipients had a 2.7% rate of hospitalization or emergency department visit compared to 5.6% of placebo recipients, which was highly statistically significant. The benefit was evident regardless of the infecting variant and the vaccination status. Treatment appeared very safe, although of course the study lacked enough participants to look for rarer side effects.

A couple of caveats as usual. This study was part of the ongoing TOGETHER trial, which has an adaptive trial design. This is a more efficient trial design method to test multiple treatments for a given condition; FDA provided guidance for this a little over a year before the pandemic began. Secondly, I was very confused by a NY Times article commenting on statements by the drug's maker referring to conversations with the FDA that could delay drug approval. What was stated in the article doesn't sound anything like what FDA regulations require, so I suspect there is more to this story than what we hear from big pharma. Still, it could signal a delay in drug availability. In general, this approach to covid treatment could be a game-changer for other infectious diseases, so I'm looking forward to more studies of interferon therapies.

New Immunization Schedules from CDC

As always at this time of year, CDC's Advisory Committee on Immunization Practices released updated immunization schedules for children and adults. It has the seal of approval from multiple organizations including the American Academy of Pediatrics. I don't see anything particularly controversial, but it does have recommendations for routine incorporation of covid-19 vaccination for all ages 6 months and above. It should be required reading not only for primary care providers but also for sub-specialists, since they need to be aware of recommendations for people with immunocompromising or other high risk conditions. Individual jurisdictions will decide how this is implemented for circumstances such as public school attendance.

More Good News on Vaccination and Pregnancy

A few new studies add more evidence for the benefits of vaccines for pregnant individuals. First, investigators from multiple countries reported that covid-19 vaccination during a time when omicron was the predominant variant significantly reduces severe symptoms, complications, and death in that population. In another study, maternal covid vaccination also was beneficial for their newborn infants, with lower rates of infection and hospitalization during the first 6 months of life.

We also have additional new data that pertussis vaccination of pregnant individuals offers significant benefit to their newborn infants. Since maternal immunization was recommended in the US in 2012, rates of pertussis particularly in the age group less than 2 months have decreased considerably. Note that this is the age group where the most severe disease and deaths have been seen in the past.

I hope those providing care to pregnant individuals will stress the benefits of these vaccines both for these individuals as well as their newborns.

Allergy Labels: Garbage In, Garbage Out

Please excuse my bias, but a study just published touched on one of my all-time pet peeves: labelling someone with a drug allergy without documenting the clinical circumstances. Often it isn't even a true allergy. This particular report looked at a sampling of children labelled as allergic to penicillin and enrolled in primary care practices affiliated with Texas Children's Hospital and Children's Hospital of Philadelphia. Not surprising (to me), the description of details of the reactions were dismally incomplete, and very few children had this label removed. However, of the children delabelled by either the primary care provider or an allergist, over 90% tolerated subsequent penicillin doses just fine. I issue a plea to all healthcare providers to not just label someone as allergic to a drug without providing a detailed description of the reaction. It makes it so much easier to assess risk of drug therapies in the future. Failure to do so sometimes results in children (and adults) being prescribed suboptimal treatments for future illnesses.

A Picture is Worth a Thousand Words

I told you I would get back to today's NFL activities, just bear with me a moment.

I have long been interested in the graphical display of information. In another part of my life, I led workshops on how to use PowerPoint and other slide presentations more effectively (short synopsis - PowerPoint was designed as a tool for advertisement, presenting a biased view, rather than to encourage critical thinking by the audience). Florence Nightingale published a terrific graph in 1858 detailing causes of death in the British military during the Crimean War. Offshoots of this graphing type are used to represent excess causes of death even today in the covid pandemic. A print of Charles Joseph Minard's map of Napolean's Russian campaign hung in my office for many years and now stares at me just beside my home work desk.

How does this relate to football? Another pretty good pictorial representation appeared in the 2005 report of an MRSA outbreak among St. Louis Rams players. Although it involved just a few players, you can see in Figure 1 how things played out. Of course, MRSA is a real problem in sports as well as in the general population. We still don't have effective preventive measures, though common sense, soap, and water go a long way in keeping everyone healthy.

The picture/1000 words title of this heading is a common aphorism that I think most of us agree is true. I had trouble pinning down the origins of this adage, variously attributed to Leonardo da Vinci, Ivan Turgenev, Henrik Ibsen, and even Napoleon Bonaparte - quite the collection of suspects. However, the credit for the verbatim aphorism I think belongs to the January 10, 1918, edition of a newspaper from my hometown. And, no, it's not a coincidence that you don't see any pictures or graphs in today's post. If you find yourself wishing I had thrown in a few, you've proved my point!

Tag: pertussis

Happy Autumnal Equinox 2

Pertussis