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Published on Leave a comment on I’m Optimistic

It was a busy week for infectious diseases, not in the sense of more outbreaks but rather more epidemiologic and vaccine data that point to better health for the future.

The big topic of the week was the Advisory Council on Immunization Practices regular February 2-day meeting. In retrospect, pediatric healthcare providers won't have any major new recommendations to work with; those are likely coming following the next meeting the end of June. I wasn't able to view as much of the meeting as I had hoped, patient care interfered a bit, but I did review all the presentations for those that I missed hearing live. Let's dive in.

ACIP

The Council discussed 9 different topics, but only 3 involved voting: COVID-19 vaccines (vote in favor of a spring vaccine for some high-risk people), Chikungunya vaccine (vote for use in some US adult travelers and in laboratory workers), Td vaccine availability for those with contraindications to receiving pertussis vaccine (discussion followed by a vote regarding the Vaccines for Children progam), influenza vaccines, polio vaccines, RSV vaccines for adults, meningococcal vaccines, pneumococcal vaccines, and the new Vaxelis combined product for diphtheria, tetanus, pertussis, polio, Hib, and hepatitis B. I'll expand on just a few of these topics. (Note all of the graphs/figures below are from the ACIP web site presentation slide link for the February meeting.)

RSV

We saw the most up-to-date representation of RSV epidemiology, showing that the epidemic curve for this year looks a lot like prepandemic years (see last presentation in RSV session).

A good part of the discussion centered on risk of Guillain-Barre syndrome following vaccine, compared to risks of GBS in the baseline population. Both are rare events, but I think at this point it is reasonable to conclude that GBS is a rare risk of RSV vaccination, though not enough to outweigh benefits for high risk populations.

A quick look at the benefits versus GBS risks for adults > 60 years of age (Melgar presentation from RSV session):

Note risks might vary with vaccine type - hard to know with rare events and large confidence intervals, plus both in the ballpark of background GBS numbers.

Influenza

This session was interesting for me to see a preliminary assessment of vaccine effectiveness for the 2023-2024 flu season. I'll just show you an overview of VE in the pediatric population; note that multiple methodologies are used to measure VE. (See slides from Frutos presentation in the influenza section.)

This is good VE for flu, certainly the CDC and WHO were on track for choosing the best combination of strains for this season. Look for the vote for next season's vaccine composition in June.

Meningococcal Vaccines

The focus of the discussion was how best to incorporate meningococcal B vaccine now that we have an approved combination vaccine containing this serogroup. Here are the main options discussed, from the 1st Schillie presentation:

The issues are complex, primarily due to 3 factors. First, meningococcal group B infections are extremely rare; traditional cost-effectiveness models show that meningococcal B vaccination in the US is by far the most expensive vaccine; very few cases are prevented due to the rarity of infection. Second, vaccination at age 11-12 risks significant waning of immunity by the age for peak meningococcal disease in adolescents; it might make sense to move the first dose to a later age. (The main argument against this is the confusion caused by eliminating the long-standing practice for vaccination at age 11-12, perhaps lowering overall vaccine acceptance.) Third, it is clear that not all meningococcal disease risk in adolescents is equal: college attendance is prime, but there are other behavioral risk factors (1st Schillie presentation):

The discussion was mainly to hear input from all stakeholders and then go back to the drawing board. Expect a vote on this at the June meeting - it will greatly impact your summer vaccine guidance for adolescents and young adults.

COVID Vacines

This section of the meetings seemed to garner the most publicity. Of course most of the results presented dealt with adults, given the relatively lower risk for bad outcomes in children plus low rates of vaccinations. Most helpful I thought were the discussions about covid VE in recent months looking at the fall monovalent vaccine.

These are great numbers. Also mentioned was the fact that waning of efficacy hasn't been seen yet, but that could just be a result of not having enough time to pass since the fall vaccine. Other good news is that in vitro studies suggest that the current monovalent vaccine is likely to protect against newer variants.

The official recommendations from CDC now state

Special situation for people ages 65 years and older: People ages 65 years and older should receive 1 additional dose of any updated (2023–2024 Formula) COVID-19 vaccine (i.e., Moderna, Novavax, Pfizer-BioNTech) at least 4 months following the previous dose of updated (2023–2024 Formula) COVID-19 vaccine. For initial vaccination with Novavax COVID-19 Vaccine, the 2-dose series should be completed before administration of the additional dose.

That "should" wording was the subject of much debate, finally choosing this wording more for simplicity of recommendations. The gnashing of teeth came about for a good reason - people in the lower end of this age population who do not have underlying risk factors will have less benefit from a spring vaccine because rates of bad outcomes in the post-pandemic period are lower.

Recommendations for younger people with moderate or severe immunocompromise have slightly different wording:

  • People ages 12–64 years who are moderately or severely immunocompromised may receive 1 additional dose of any updated (2023–2024 Formula) COVID-19 vaccine (i.e., Moderna, Novavax, Pfizer-BioNTech) at least 2 months after the last dose of updated (2023–2024 Formula) COVID-19 vaccine indicated in Table 2. Further additional doses may be administered, informed by the clinical judgement of a healthcare provider and personal preference and circumstances. Any further additional doses should be administered at least 2 months after the last updated (2023–2024 Formula) COVID-19 vaccine dose.
  • People ages 65 years and older who are moderately or severely immunocompromised should receive 1 additional dose of any updated (2023–2024 Formula) COVID-19 vaccine (i.e., Moderna, Novavax, Pfizer-BioNTech) at least 2 months after the last dose of updated (2023–2024 Formula) vaccine indicated in Table 2. Further additional doses may be administered, informed by the clinical judgement of a healthcare provider and personal preference and circumstances. Any further additional doses should be administered at least 2 months after the last updated (2023–2024 Formula) COVID-19 vaccine dose.
  • For all age groups, the dosage for the additional doses is as follows: Moderna, 0.5 mL/50 ug; Novavax, 0.5 mL/5 ug rS protein and 50 ug Matrix-M adjuvant; Pfizer-BioNTech, 0.3 mL/30 ug.

As an aside and not receiving much media attention, a new report showed that vaccine mandates didn't help and probably hurt. States with vaccine mandates didn't have higher covid vaccination rates and actually had lower covid booster uptake and flu vaccination rates. Yikes!

Nipah Virus

Never heard of it, or hard-pressed to find facts at the tip of your tongue? Most providers in the US don't need to know much about this bat-borne virus, but if you have any patients planning a trip to Bangladesh you may want to advise them not to consume raw date palm sap (not on my list of delicacies so far) and to stay away from pigs.

NiV gets its name from the village of Sugai Nipah in Malaysia, site of a 1999 outbreak highlighted by cases of encephalitis in pig farmers. Outbreaks typically occur in Bangladesh and India. Now, the World Health Organization reports that 2 individuals, including a 3-year-old girl, have died from the infection after consuming raw date palm sap. The sap likely was contaminated with fruit bat droppings laced with NiV. In addition to signs and symptoms of encephalitis, typical findings are those of nonspecific febrile illness. Diagnosis is difficult until/unless encephalitis findings appear. It's a relatively uncommon infection even in Bangladesh, but mortality is high.

Good Attitudes

It's a sign of our times that I was pleasantly surprised to see a vaccine attitude survey with good news. Investigators from RAND corporation, University of Iowa, and CDC performed an online survey of 1351 parents to assess their willingness to have their children 5-18 years of age receive a vaccine to prevent Lyme disease. About two-thirds of parents definitely or probably would vaccinate their children. The boldface numbers below show statistically significant predictors of willingness to have their children receive Lyme vaccine, with willingness of the parent to receive the vaccine the strongest predictor.

In case you were wondering, for the purposes of this survey the high incidence states were Connecticut, Delaware, Maine, Maryland, Massachusetts, Minnesota, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, Virginia, Washington D.C. (yes, I don't need to be reminded it's not a state), West Virginia, and Wisconsin. They also looked at states characterized as "emerging" Lyme disease states (Iowa, Ohio, Illinois, Indiana, Michigan, North Carolina), but this group had a slightly lower rate of willingness than in high incidence states. Lyme vaccine trials in the pediatric and adult populations are ongoing, so don't be surprised if parents and children have this option in the next year or so.

Speaking of attitudes, take a look at AAP's new guidance for improving vaccine communication and uptake. It has an excellent literature review and describes various strategies that pediatric healthcare providers can use to improve vaccine acceptance. It is still true that different studies sometimes have reported different conclusions on how best to discuss vaccine hesitancy with parents, likely because it is very difficult to design studies that deal with such subjective issues in a uniform manner.

WRIS

Winter respiratory infection season is still chugging along, mostly due to influenza which is stubbornly persisting in scattered areas in the US. What a crazy patchwork!

New Covid Isolation Guidelines

Maybe this has overshadowed everything in the news. I've discussed this recently in the blog and was expecting the new guidelines to come in April, but CDC bumped it up by a month. It incorporates new information about covid epidemiology, hospitalization rates, and outcomes with balancing for impacts on the economy and on school and work attendance into a comprehensive guideline for all respiratory infections. So, no longer do we have a specific number of days after covid diagnosis to remain out of school or work. The document has multiple links and is pretty complicated. The CDC's press release is a good summary, however. Note that vaccination is still stressed heavily, though I expect it will be ignored by the same hardcore group of antivaxxers. Here's the quick blurb:

"When people get sick with a respiratory virus, the updated guidance recommends that they stay home and away from others. For people with COVID-19 and influenza, treatment is available and can lessen symptoms and lower the risk of severe illness. The recommendations suggest returning to normal activities when, for at least 24 hours, symptoms are improving overall, and if a fever was present, it has been gone without use of a fever-reducing medication."

I am very much in favor of these new recommendations. Circumstances have changed, and we have learned a lot from management of the pandemic these past few years. I just hope our vaccination rate will improve and that people with any respiratory symptoms at all will be aware that they can pose a significant risk to others who may have circumstances putting them at high risk for hospitalization or death from respiratory viruses. Also, please note this only applies to community settings; there are no changes for healthcare settings.

Squirrel Redux

If I were superstitious, I wouldn't mention the fact that my neighborhood squirrels still have not attacked my newly-positioned bird feeder. I was bemused by an article in the Local Living section of the Washington Post last Thursday, clearly written by a squirrel lover. Squirrels do have value, and I have no desire to wipe them off the face of the earth. I just don't want them eating all my bird seed.

A friend of mine in South Carolina with an array of bird feeders and birds also has come to terms with squirrels, albeit somewhat differently than my crazy solution. He just monitors things, and when the squirrels reach a point that he feels they become a significant barrier to maintaining bird happiness and seed access, he uses a humane trap to collect squirrels and then release them far from his neighborhood. I won't disclose where he releases them, but it sounded like a good place for squirrels and unlikely to bother too many people. I wonder if any of them found their way back to him.

A downy woodpecker said hello to me last week.

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Published on 2 Comments on Happy Holidays!

I'm putting this post together on Father's Day, and tomorrow is Juneteenth, a holiday increasingly recognized in the US. Today two of my 3 sons are farther away than usual, one in Berlin, Germany, at the Special Olympics World Games and another working in healthcare in Mekele, Ethiopia. The third member of the triumvirate remains in the eastern US time zone.

Can anyone guess which state was the first to make Juneteenth a permanent state holiday?

Influenza Rising in Southern Hemisphere

The most recent World Health Organization update on influenza, published on June 12 with data current as of May 14, not surprisingly shows an uptick in flu activity in sections of the southern hemisphere. The influenza AH1N1 2009 pandemic strain and B Victoria lineages predominate, meaning we are likely in good shape from a vaccine standpoint for next winter in the US.

RSV and covid haven't increased to the same extent as flu in the south, for the most part.

Polio Vaccine for Travelers

'Tis the season for world travel, but I'm thinking many folks aren't aware of newer polio risks around the world. Spurred by the pandemic and various war zones, polio vaccination has waned. Also, as I've noted in the past we're seeing vaccine-derived polio disease via transmission from recipients of the oral live polio vaccine. The CDC continues to update polio vaccine recommendations for travelers. Twenty-nine countries around the world have circulating poliovirus, but in addition to the "usual suspects" the list now includes both Canada and the United Kingdom.

Certainly the risk can vary in settings within these countries, but primary care providers should remember to discuss vacation plans with families, not just out of interest but to make sure they are informed of any risks and where to find resources. Make sure all children are up to date on immunizations, including polio, and some adults may wish to receive a one-time killed polio vaccine booster if traveling to a high risk country.

'Demic Doldrums

Here in the US we continue with our low levels of SARS-CoV-2 circulation in most jurisdictions; now we rely primarily on ED visits and hospitalization rates for any early warning given our lack of other good community monitoring tools. The FDA VRBPAC group met on June 15 to advise on composition of the next covid vaccine, and I was able to attend most of the meeting including the important parts of the discussion sessions. All 3 US vaccine manufacturers (Moderna, Pfizer, and Novavax) presented data.

As most providers know, the XBB sublineages (XBB represents a recombination of omicron strains) now predominate; the ancestral strain has virtually disappeared from circulation in humans, as have all subsequent strains except for the omicron lineage. Without going into perhaps agonizing detail, most authorities agree that covid vaccines for the near future should focus on the XBB sublineage. The vaccine manufacturers have a fair amount of preliminary data on immunogenicity of XBB-containing vaccines. Results suggest good safety signals and good neutralizing antibody activity against currently circulating XBB strains. Less data are available for memory B- and T-cell responses to these vaccines, and nothing substantial so far on XBB vaccination of children. Work continues, and we should see more about pediatric XBB vaccination in the next month or 2.

A very important part of the presentation has to do with cross-reactivity of antibody among the various XBB strains that were tested. Because of this, a monovalent vaccine with any XBB strain is likely to be effective against these closely related sublineages. Since among other reasons all 3 companies had the most experience with the XBB.1.5 vaccine and can readily ramp up vaccine production for this product, the VRBPAC members unanimously voted to go this route and the FDA officially signed off on this recommendation. Next up is a discussion at the ACIP meeting on June 23, but don't expect any vote or final recommendations at this session. That should come a bit later. In particular, we will need guidance on pediatric use, combined use with other vaccines such as for influenza and RSV, and whether to recommend for all or just for certain high-risk populations.

Last week I perhaps dissed the CDC's use of color in their depiction of variants, but now I need to acknowledge I was wrong. The most recent MMWR had some nice graphics. The graph below not only shows the colorful distribution of variants but also the relatively low numbers of cases recently (with the caveat that testing in general is less now than in 2022).

As can be seen, we have been in an omicron world for some time, with XBB now in charge.

Quickly, a few other covid notables from last week:

Juneteenth

Perhaps not what you would have guessed, but my home state of Texas was the first to make Juneteenth a permanent state holiday, in 1980, which was decades before most of the rest of the country. I left Texas in 1984 and parts of it now are unrecognizable to me, but it's easy to understand why that state was out in front on Juneteenth. The original event was June 19, 1865, in Galveston, TX, when Union troops arrived and finally enacted the January 1, 1863, Emancipation Proclamation and freed slaves in Texas. In my childhood, unless you kept yourself under a rock, if you lived in Texas you knew about Juneteenth.

Happy Father's Day to all fathers out there, and to everyone please use Juneteenth to reflect on its many lessons that continue to challenge us to do better.

Published on Leave a comment on Calm Before the Storm?

Frontline pediatric healthcare providers probably wouldn't think things are calm given our current onslaught of RSV and influenza cases crowding physician practices, emergency rooms, and hospitals. However, we are in a bit of calm of sorts for covid. Covid cases actually are decreasing in the UK and the US. Lacking a reliable crystal ball, we'll all need to wait to see whether the next few months will bring a significant rise in covid cases. In the meantime, let's explore a couple areas of interest and confusion.

How Well Do the Bivalent Boosters Work?

More time is needed for the definitive answer on this. The discussion has been going on for months, but this past week we saw posting of 2 preprint articles suggesting, based on immunologic testing, that they may not be much better than the original vaccine used as a booster, at least in terms of preventing illness after infection from some of the newer variants. This is actually what was suspected all along. The bivalent vaccine to stimulate immune response to the spike protein from BA.4/BA.5 was hoped to be a bit more effective to prevent severe disease caused by future virus variants. Carolyn Johnson's explanation of the issue in the Washington Post was excellent, please check it out. It is important to recognize that these 2 studies were based on very few individuals and have not undergone peer review. However, the reports are from generally reliable teams at Columbia University/University of Michigan and Beth Israel Deaconess Medical Center. I don't expect big changes in the results once the peer review is completed.

I want to expand on one concept mentioned as an explanation for the findings in both articles, that of immunologic imprinting. This phenomenon also has been referred to as original antigenic sin.

This imprinting is very different from filial imprinting, like baby ducks following the first thing they see after birth. Original antigenic sin refers to the 60+ year old observation that our immune systems like to use the memory of our response to an infection with an antigen (virus in most cases) when infected at some future time with a variant of that antigen. It could potentially interfere with a more robust immune response to that new variant. Of course, covid didn't exist when it was first described; the main subject was influenza at that time. Scientists developing new vaccines have been well aware of this phenomenon for decades. Covid vaccine development has incorporated this concept.

A key point: although it's possible the bivalent vaccines aren't that much better than the original vaccines when used as boosters, any booster is far better than no booster. Please encourage everyone eligible to be fully vaccinated and boosted for COVID-19.

[I realize I haven't mentioned this in a while, but some may wonder about my frequent use of Wikipedia in my links. For many medical issues, I find Wikipedia to be highly accurate plus a little more understandable to non-medical folks than virtually all other sources.]

Should We Worry About Polio in the US?

In general, no, but anyone lacking full vaccination against polio needs to beware. A few years ago it would have been hard for me to imagine ever saying that, but a combination of war, politics, natural disasters, and apathy make paralytic polio a real possibility now. Wild-type polio transmission was eliminated in the western hemisphere in 1991, and it still is, but failure to eradicate it elsewhere has led to vaccine-derived poliovirus causing paralytic polio across the world, including in the US. (Paralytic disease, the most severe form of polio, develops in less than 1% of infected individuals.)

For those unfamiliar with the disease (few clinicians have seen an active case of paralytic polio, unless they have worked abroad), remember that we have had 2 types of polio vaccine for many years. The live polio vaccine (aka Sabin vaccine, developed in 1961) is a weakened version of the wild virus, given by mouth, and requires viral replication in our bodies to produce immunity. It is particularly helpful in achieving immunity in populations difficult to reach by widespread immunization because the vaccine virus is excreted in stool and can be spread to others. That's mostly a good thing, but sometimes this vaccine-derived strain can undergo transformation to increased virulence and actually cause disease in others. A killed vaccine given by injection (aka Salk vaccine, developed in 1955) also is effective though slightly less so than the live vaccine. The live vaccine has not been used in the US since 2000; all polio immunizations in the US, and in most other developed countries, utilize the killed vaccine.

Even though most of us in the US are immunized and therefore protected against polio, wastewater surveillance in New York City suggests that the vaccine-derived virus is circulating in at least 5 counties, putting un- or under-immunized people at risk for paralytic polio. This situation likely is occurring elsewhere in the US, but so far we lack comprehensive wastewater polio reports. Data from London suggest the problem is widespread.

The pandemic and ongoing anti-vaccine rhetoric has disrupted vaccination programs in the US. Let's hope we don't see more cases of paralytic polio in the US.

Interested readers can learn more about the history of polio from the Global Polio Eradication Initiative.

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