As summer approaches, infectious diseases travel risks are growing. Now more than ever it's important to check recommendations for protection.
But first, I had an interesting couple of days listening to a large chunk of the ACIP meetings this past week. I was pleasantly surprised that it went pretty well with minimal evidence of adverse effects of cost cutting and no evidence of lack of transparency or significant censorship. I'll give my take on the big picture of ACIP as well as some of the important discussions and decisions that impact child healthcare. I tried to distill the meeting points to essentials, but it's still long-winded. Apologies.
Advisory Committee on Immunization Practices Meeting April 15-16, 2025
The original meeting scheduled for February was planned to last 2 1/2 days but was shortened to 2 days, and it was jam-packed and fast-moving. Eleven different vaccine topics were on the agenda: mpox, Lyme disease, influenza, COVID-19, pneumococcal, HPV, CMV, meningococcal, RSV adult vaccines, RSV maternal/pediatric vaccines, and chikungunya. There was also a brief presentation on the measles outbreaks. The only votes taking place were for meningococcal, RSV adult, and chikungunya vaccines. Others may have votes at the regular June meeting if the specific products being discussed are approved by FDA as seems likely next month for a few products. All the slides are available at https://www.cdc.gov/acip/meetings/presentation-slides-april-15-16-2025.html.
General
Most importantly, ACIP still exists and appears relatively unscathed. The presentations contained a lot of information, sometimes a little too quickly for adequate digestion by those unfamiliar with minutiae of specific vaccine immunology. I did feel there was adequate time for discussion and questions from committee members. A few things I was particularly looking for:
- Evidence of Funding and Personnel Cuts - This appeared minimally, maybe just with respect to AV support. There were 2 instances in the streaming where lack of AV support stalled the meeting briefly.
- Conflicts of Interest - ACIP and CDC have always been very strict about this. In the past, some of the members had worked on vaccine trials, but with new members appointed last year (well before the presidential election), it seems that fewer members have that background. All were required, as usual, to state any COIs up front. None had any noteworthy conflicts, but a few members did abstain from certain individual votes based on some potential appearance of COIs, for example having some involvement with a vaccine a decade previously, or serving on a data safety monitoring board for a vaccine in the distant past. I wondered if those individuals were bending over backwards to avoid any opportunity for lay press and politicians to falsely claim they had COIs.
- Membership - A couple new committee members were added, nothing controversial to my eye. I was also intrigued to see a new nonvoting ex officio member representing the FDA, Dr. Hoag. Usually the FDA representative is someone directly involved with reviewing vaccines and is an expert in both FDA regulations and all aspects of vaccines. In contrast, Dr. Hoag is a political appointee with a background in sports medicine and epidemiology.
- DEI and "Wokeness" - One of the standard evaluation measures used by the CDC/ACIP is an "Evidence to Recommendations" assessment that includes 7 domains: (is the disease) a public health problem; benefits and harms of vaccination; values (of the target population); acceptability (to key stakeholders); resource use; equity; and feasibility. I was particularly worried about whether the important equity domain would survive, and I'm happy to report that it did. In terms of wokeness, I did see that CDC presentations used the term pregnant "women" rather than pregnant "people." Also, Dr. Hoag used the term "monkeypox" for mpox, perhaps just a slip for someone who hasn't been involved with mpox at all.
- Public Comment Session - As for most meetings, 30-minute public comment sessions provide an opportunity for 10 individuals to speak for 3 minutes each. If more than 10 people apply to comment, the speakers are chosen by lottery which was the case for the single public comment session on April 16. Usually the speakers are a large mix - some from organizations and some individuals, some pro-vaccination and some anti-vaxxers, some well-informed and some misguided. The mix was very different this time around: all 10 speakers were very clearly in the pro-vaccine camp. Two were even from the same organization. For this to have resulted from a lottery process implies that the overwhelming number of applicants were pro-vaccine. I haven't heard about any unified effort to flood the ACIP public comment applications, but I suspect that the dramatic changes in HHS and CDC served to activate a large backlash from people who recognize the value of vaccines; after all, they do represent the majority of the US population.
- Balancing Simplicity With Individuality of Recommendations - This is nothing new, but it was even more evident at these presentations that CDC is trying to simplify vaccine recommendations, including harmonizing among various risk populations. They hope to improve on the problem that occurs when recommendations vary for different individuals and it becomes difficult to explain all that to healthcare providers as well as to the general public. I think we'll see even more of a move towards harmonizing recommendations among different risk groups and less advice to use shared clinical decision making. I'm a bit sad about that, it probably results from many folks being tired of hearing about vaccines in general plus clinicians feeling like they don't have the time to explain this to their patients. On the other hand, there is a movement to have less universal recommendations, such as for covid vaccination, with more emphasis on vaccinating high risk groups. See the covid section below for more information. The modern practice of medicine has always involved translating general results from studies of groups of individuals to use in a specific patient who may or may not exactly fit the subjects in a research study. That requires thought and time. The best clinicians find a way to understand the evidence behind vaccine recommendations and incorporate this into shared clinical decision making.
Mpox
The discussion revolved around approval for mpox vaccine in the 12-17 year old age group based on subsequent vaccine trials, a pretty straightforward question that was approved. I did find a few of the slides helpful in understanding the history and recent trends in the outbreaks. Both the clade 1 and clade 2 outbreaks are currently problematic.
Recommendations differ for outbreak versus routine vaccination strategies for adolescents and adults at risk for mpox.
Influenza
Regular readers will recall that the usual annual FDA VRBPAC meeting to choose the components of next year's flu vaccine was cancelled, and the strain choices were determined without advisory committee input. The ACIP discussion centered on home administration of FluMist, the live attenuated intranasal flu vaccine. The data are pretty good, but the devil is in the details - all kinds of regulatory and tracking details, including but not limited to the fact that some states won't allow prescriptions across state lines, so if you live in West Virginia but your primary care provider is in Maryland you might have trouble. Also, there can be lots of bumps in the road ensuring that the vaccine was in fact administered at home and logged into the individuals vaccine records. We're going to hear more about this in coming months, hopefully decided well before the next flu season.
COVID-19
This discussion probably got the biggest headlines. First, some general points.
Most of our population has immunity to covid, either by vaccine, infection, or both.
As the bottom statement indicates, vaccine effectiveness should focus as what the added benefit of vaccination is for a population with pre-existing immunity. Unfortunately, given the very small numbers of children receiving any covid vaccines recently coupled with the good news that events like hospitalization and deaths are relatively infrequent in children infected with SARS-CoV-2, we don't have enough data to make any VE estimates in the pediatric population. Here's the adult data:
CDC presenters noted that we experienced an increase in virus circulation in late summer 2024 just before the 2024-25 vaccines were approved and available. Natural infection during this time may have increased population immunity against the most recent strains and could have caused measured VE to be lower than if this surge had not occurred just before most people received the new vaccine.
As I've said in numerous other posts, if one looks at the impact of covid vaccination on individual pediatric patients, rather than at a population and cost-effectiveness level, the benefits of vaccination far outweigh the risks; but, it's relatively expensive to vaccinate all children, looking purely from a cost-effectiveness standpoint. Note that the cost-effectiveness studies for pediatric covid probably are similar to those seen for universal meningococcal vaccination for adolescents - small numbers of cases so higher cost of prevention, even for a more deadly infection like meningococcus.
Also, it's worth remembering that covid deaths in children are in the same ballpark as influenza-associated deaths in the US (no final data yet from this year's flu season).
Previously I've mentioned how the UK has a much more restrictive use of covid vaccines, coming from the population-based approach with the National Health Service paying for all recommended vaccines. One of the CDC presenters had a nice comparison of covid booster recommendations from around the world. I'm glad I don't have a child or grandchild living in Australia.
What is being considered is now changing the US recommendations to look more like these other countries, without a blanket recommendation for certain low-risk groups, including healthy children, while still allowing anyone who wishes to receive a vaccination. If this is ultimately the recommendation, it seems likely that the low-risk populations will have to pay out-of-pocket for the vaccine, disadvantaging our low income families and worsening health equity.
As you might surmise, my bias is still to recommend covid vaccines for healthy children.
HPV
Again no votes on the human papillomavirus vaccine, but a lot of discussion and confusing options for what's to come which could involve changing to just 1 vaccine dose being routinely recommended. First, some really good news for VE. If you compare the prevalence of the 2 HPV genotypes represented, the HPV vaccine has resulted in a dramatic decrease over the past 10 years.
I'll spare you the tremendous amount of modeling studies that were discussed and just focus on conclusions that basically came down strongly in favor of switching to a single dose vaccine schedule, even using a worst-case scenario model for vaccine efficacy and duration of protection. Also, if the 1-dose protocol wasn't working, ongoing monitoring by CDC would allow for new mitigation strategies before vaccine strain prevalence and new cervical cancers appeared.
However, here's where another concern about budget cuts appeared. One of the committee members asked whether CDC will still be able to collect this data going forward, and the answer was a non-reassuring yes, "as far as we know."
A good deal of time was spent on the harmonization of recommendations, particularly with respect to the "adolescent platform" of regular visits and how a proposed recommendation that lumped 9-10 year-olds into the recommendation with the current 11-12 yo start of HPV vaccinations would disrupt this platform of adolescent primary care visits. There seemed to be large differences of opinion among stakeholders here. Expect a vote at the June ACIP meeting.
Measles
No new data here, but yet another comment on resources when discussing trying to get the various outbreaks under control. A CDC member stated they were "scraping to find resources" to handle things.
Meningococcus
By far the most complicated, with a new pentavalent vaccine on the launching pad and a multitude of discussion about how this could be accomplished without asking primary care practices to stock up to 5 different meningococcal vaccines. A key take-home for primary care providers: groups A, C, W, and Y vaccines are interchangeable, but meningococcal B vaccines are not - you really need to give a second dose of meningococcal B vaccine using the same manufacturer as the first, for both pentavalent and monovalent products. So, we potentially will have 2 pentavalent vaccines containing group B plus 2 monovalent group B vaccines. This is a potential nightmare for private practices in terms of stocking vaccines, and a potential problem for managing college outbreaks where one needs very accurate vaccine records to know which group B vaccine to use for at-risk students. Most colleges require this information up front, certainly it isn't very feasible to find missing information in a timely manner during a meningococcal outbreak in a college dorm.
I'd expect some new wording for meningococcal vaccines to be approved at the next (June) ACIP meeting, likely a simpler, harmonized recommendation.
Other discussions centered around another quadrivalent conjugate vaccine for high-risk infants, likely to be approved by FDA next month. The ACIP plans to discuss at the June meeting if FDA approval is granted.
Next Steps
The votes need to be approved by CDC, usually a task carried out by the FDA Director. However, this spot is vacant, filled only by an acting director who is not participating in any formal duties. It looks like the approvals, if they occur, will emanate from a higher bureaucratic level.
More Measles Milestones
But certainly nothing to celebrate. In the US, we ended the week at a round number, 800 confirmed cases; 11% have been hospitalized.
We are up to 25 jurisdictions reporting cases, and a total of 10 outbreaks (defined as 3 or more connected cases). Still no signs of slowing down.
Texas alone is up to 596 cases including 36 added in the past week. It seems likely the US will surpass the 2019 total of 1274 cases, which was the highest since the US was declared measles free in 2000. Meanwhile, Canada might be in even worse shape, largely due to measles in Ontario. They are up to 880 cases this year, although this total includes 132 probable but not yet confirmed cases. It is already the highest total since Canada was certified free of endemic measles transmission in 1998.
Measles is problematic in almost the entire world now. For travel in Canada and the US, check destinations to determine whether early vaccination for infants and children is warranted.
Yellow Jack is Back - New Warning
Last week CDC upgraded their traveler warning for South America to Level 2 - Practice Enhanced Precautions. Colombia reports 75 cases with 34 deaths since September 2024, likely an undercount, and new areas of Bolivia and Peru now have yellow fever cases reported. I worry that travelers and clinicians can't keep up with new yellow fever vaccine recommendations, it's confusing and changing.
For clinicians unsure about clinical findings of yellow fever, the CDC Yellow Book is an excellent resource. (It's called the Yellow Book because the original print version had a yellow cover; now it's mostly black.)
Ignorance is Bliss versus Knowledge is Power
One might think that having my background in infectious diseases is helpful in planning travel. Or, if you side with my long-suffering wife, it might just be the bane of your existence. We have travel plans to various areas planned in the next several months. I'm not too worried about measles, we both had natural infection as children and I know that my measles IgG titer was very high a few years ago. Unfortunately vaccinations won't help us with the list of other infections to which our itinerary might expose us: Vibrio vulnificus, chronic wasting disease, Cryptococcus gattii, to name a few. Fortunately, none are very likely; I'll concentrate on sun protection and keeping well-hydrated.