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A summary of presentations from the weekly Summit partner webinars

April 4, 2024 – The latest Summit Summary

Respiratory Virus Surveillance Update – Katie Tastad (CDC)

Katie Tastad, PhD, MPH, Influenza Division, Domestic Surveillance Team, CDC, gave an update on seasonal influenza, swine flu, and highly pathogenic avian influenza virus.

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Surveillance of Outpatient Respiratory Illness (See: FluView)

  • Influenza-like Illness (ILI), which monitors fever plus cough or sore throat
    • Nationally, ILI remains above baseline
    • However, ILI has been declining over past four weeks
  • ILI by age
    • ILI is decreasing in those ages 0–4 years, 5–24 years, and 25–49 years
    • ILI in the 50–64 and 65+ age groups remained stable from previous week

Surveillance of Outpatient Respiratory Illness Activity by Jurisdiction for week 12

  • No states with very high activity
  • Nine states with high ILI
  • Four states with moderate ILI
  • Twenty states with low
  • Twenty-two states with minimal ILI

Virologic Surveillance

  • Surveillance from clinical labs
    • The percentage of clinical lab specimens that are testing positive for flu is decreasing overall
    • Additionally, flu percent positivity in the tests is decreasing
  • Surveillance from Public health labs
    • This current season has been predominated by influenza H1N1
    • There is also more influenza B in circulation, as well as influenza AH3N2 circulating

Surveillance of Hospitalizations

  • National Healthcare Safety Network (NHSN)
    • Hospitalizations due to lab-confirmed influenza have been decreasing since January
    • Week 12 had just over 5,700 patients admitted to the hospital with lab confirmed flu
  • FluServNet – this system conducts population-based surveillance in select counties in 14 states that represents about 9% of the U.S. population
    • Cumulative hospitalization rates due to influenza for this season so far are 72.2 per 100,000 population
      • The rate is second highest when compared against previous end of season rates for week 12
      • The rate is highest among adults age 65+ years (196.9 per 100,000 population), followed by adults ages 50–64 years (86.1 per 100,000 population), and children ages 0–4 years (75.3 per 100,000 population)

Surveillance of Mortality

  • National Center for Health Statistics
    • During week 12, 5% of the deaths that occurred were due to influenza
    • Deaths have decreased drastically since the peak in January
  • There have been 126 reported influenza-associated pediatric deaths
    • Of those 126 deaths, 69 were associated with influenza A viruses
    • Of those 126 deaths, 55 were associated with influenza B viruses
    • Two deaths were associated with influenza A/B coinfections
  • Deaths were reported from all regions of the country
    • Highest death rate was in the southeast and the mountain regions this season

Summary

  • Seasonal influenza activity is still elevated but it is decreasing nationally
  • Nationally, the percent positivity for both influenza A and B in lab testing is continuing to decrease
  • Outpatient respiratory illness is still above the national baseline, but it is decreasing
  • CDC is recommending that everyone ages 6 months and older continue to get an annual flu vaccine as long as flu is circulating

Human Case of novel swine flu virus case in March

  • These viruses typically circulate in pigs but when they crossover into humans, they are referred to as a “variant virus”
  • The recent human case was reported to Pennsylvania Department of Health
  • First case in this calendar year
  • Patient is a child under the age of 18 years
  • Sought healthcare during the week that ended March 9
  • Presenting illness included fever, vomiting, cough, and a runny nose
  • Patient was hospitalized and has since recovered
  • Public health officials were able to determine that this patient did have swine contact prior to their illness onset
  • There has been no person-to-person transmission associated with this patient

Human Case of highly pathogenic avian influenza (HPAI) A(H5N1) virus (H5N1 bird flu) in March

  • Reported by Texas Department of State Health and Human Services; confirmed by CDC on March 30
  • Patient developed conjunctivitis around March 27 while working on a commercial dairy farm
  • H5N1 virus has been recently detected in dairy cattle, poultry, and wild birds among other animals in Texas
  • Respiratory and conjunctival specimens were collected from the patient and tested at Texas Tech University Bioterrorism Response Lab on March 28
    • Found with RT-PCR that both specimens were presumptive positive for H5 virus
  • Specimens sent to CDC for further testing
    • Confirmed as (HPAI) A(H5N1) virus, clade 2344B (what’s currently circulating among birds and poultry)
  • Patient recommended to isolate and provided with influenza antivirals (household contacts did not report any illness, but were provided with antivirals prophylactically)
  • Investigation ongoing in Texas
  • This is the second person to test positive for HPAI H5N1 in the United States
    • First case was in April of 2022 in Colorado due to exposure to poultry
  • Asking state and local public health departments to monitor people who are exposed to birds or other animals including livestock that are suspected to be infected with avian influenza viruses for 10 days after their last exposure
  • Currently there is no concern about the pasteurized milk supply
  • There are two candidate vaccine viruses for H5N1, and based on the recent sequencing at CDC, they appear to be genetically related to the variant virus

Resource Links

 

Questions 

Q: For the Texas case, was seasonal flu suspected? What prompted testing for the H5N1 patient?

Katie Tastad (CDC): I don’t think that seasonal flu would have been suspected initially since the patient only had conjunctivitis. This person worked with cattle, so I think it came from that angle rather than clinical suspicion over the conjunctivitis.

 

Q: Do the cattle appear sick at all or do they drop dead like the birds do?

Katie Tastad (CDC): I’m not a veterinarian so I’ve got a limited understanding of how this presents in animals, but they don’t drop dead from what we’ve seen so far. There is decreased milk production, which is a red flag. I’m not sure what the other symptoms are but they do develop symptoms, just not the high fatality that we see in other species.

 

Q: When do we need to start worrying about this?

Katie Tastad (CDC): It was a surprise that it would come from cattle to people. Seeing that this person who was infected had conjunctivitis and not something more severe is a good thing, and if people want to dive more into the genetic sequencing information, that’s good too. I don’t know that we could say it’s not more severe, but I think if we saw more changes in the genetic sequence then that could be problematic. Also, if we saw any person-to-person transmission, which we have not.

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Epidemiology of Measles Cases Update – Dan Filardo (CDC)

Dan Filardo, MD, Medical Officer, NCIRD, CDC, gave an update on the epidemiology of measles cases.

Resources

Measles cases so far in 2024

  • As of Friday, March 29, there were 97 reported cases from 18 jurisdictions
    • During all of 2023 there were 58 reported cases from 20 jurisdictions
  • So far in 2024 there have been seven outbreaks; “outbreak” in the U.S. is defined as three or more cases related by transmission
    • Four outbreaks have been reported during all of 2023
    • Largest outbreak this year is in Chicago within a congregate setting and shelter
      • This Chicago outbreak comprises approximately half the cases in U.S. so far this year
    • Majority of cases in the outbreaks occur among those either known to be unvaccinated or have unknown vaccination status
      • 17% of cases were among vaccinated persons
        • 12% had one documented MMR dose
        • 5% had two documented two MMR doses
      • Since 2000–2023, about 8% of all cases are among those with prior vaccination, split evenly between those with one and two doses
      • The current cases in the vaccinated are being driven by the large outbreak in thecongregate setting with vaccine failure and a high infection rate
        • This is a higher percentage of vaccinated getting sick than in past experience
      • Around 50% of cases have been those under five years
        • In 2000, the percentage of cases in those under five years was around 38–40%
        • This current higher rate is being driven by the outbreak in the congregate setting or shelter in Chicago
      • Hospitalization
        • About one in five cases are hospitalized
          • The higher risk group is children under one year of age
          • In this risk group, the number might get closer to 30%
          • No age group has seen historical data that suggests 50% hospitalization
          • This higher rate may be due to inability to isolate due to congregate setting
        • Global situation
          • Rising cases across the globe and across most WHO regions
          • European region is seeing a rise in cases, especially in western Europe and the United Kingdom
            • UK outbreak is currently documenting more than 750 cases since October 2023
          • Call to action
            • Call to action: recommendation for international travelers to be vaccinated
              • Measles is not endemic in the U.S.; outbreaks occur because of imported cases of people who become exposed to measles while outside the U.S.
              • S. residents who are traveling internationally need to be up to date on their immunizations
              • Travelers over age 6 months but under 12 months are recommended to get one dose of MMR at least two weeks before international travel
                • After first dose, follow the recommended schedule and get another dose at 12–15 months and a final dose at 4–6 years
              • Everyone over age 12 months needs two doses of MMR separated by at least 28 days (about 4 weeks)
            • Call to action: we want to maintain measles elimination and protect children from measles in the United States through robust two-dose coverage that has been historically achieved for school aged children
              • Unfortunately, school two-dose vaccination coverage has slipped from +95% to closer to 93% nationally
              • This decline puts an estimated 250,000 kindergartners nationally at risk of contracting measles
              • Overall, exemptions for childhood vaccinations rose across the country and are above 5% in kindergarteners in 10 U.S. states
            • Call to action: immunization recommendations for adults
              • What about waning immunity in older adults and how do we manage that
                • The messaging right now is just to try to get every person in the U.S. up to date with the recommendations for their age group
                • ACIP recommendations for adults who are considered low risk for measles exposure would be that they have at least one documented dose of MMR in the past
                • Adults who are considered at higher risk for measles exposure are recommended to have two doses of MMR
                  • International travelers
                  • Adults attending post-high school educational settings
                  • Adults who work in healthcare facilities
                • For adults with documented MMR doses that meet ACIP recommendations, they do not need any additional doses at this time

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Measles Exposure Update – Paul Offit (CHOP)

Paul Offit, MD, Director, Vaccine Education Center (VEC), Children’s Hospital of Philadelphia (CHOP), Professor of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, gave an update on measles exposure.

The Winter 1991 Philadelphia measles epidemic

  • There was a quick increase of cases
  • There was the first measles death in a person more than 20 years of age
    • Children were typically dying of severe dehydration, pneumonia, or encephalitis
  • Eventually there were hundreds of cases
  • The Commonwealth of Pennsylvania gave the city hundreds of thousands of dollars to educate about the importance of the MMR vaccine
  • The outbreak was centered on two fundamentalist churches: First Century Gospel and Faith Tabernacle
    • These churches did not believe in vaccination or medical care
    • Their congregation comprised large families and schools
    • They believed prayer can save from illness
  • A series of court orders were obtained that allowed physicians at CHOP or St. Christopher’s Hospital for Children, to go and assess the children from the two congregations and report back to public health
  • Court orders were also obtained to put children in the hospital
  • Court orders were obtained to vaccinate children against their parents’ will down to age 6 months—this was the first compulsory vaccination in U.S. history
  • The Commonwealth of Pennsylvania had religious exemptions in 1991
  • The pastor for Faith Tabernacle, Charles Ryder, asked the American Civil Liberties Union (ACLU) to represent them, but the ACLU refused
    • While the ACLU agreed with religious freedom, they did not agree that parents have a right to martyr their children
  • In 1991 there were 1,400 cases and 9 deaths from measles
  • Bill Atkinson of the CDC was sent to Philadelphia to try to answer whether the measles strain was unique or if it was the population not being vaccinated
    • It was shown that the children were of upper and middle class, and well cared for, but their parents just chose to not vaccinate
  • In the late spring the cases drastically subsided

Current measles outbreak in Mississippi

  • A lawyer representing the Informed Consent Action Network went to Mississippi and introduced a religious exemption
    • Previously were only medical exemptions
  • 2,100 parents immediately chose not to vaccinate
  • There has been an erosion in vaccine rates primarily because people are choosing non-medical exemptions

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Questions

Q: Data shows some of the pediatric rates are declining, but adults don’t come off unscathed with regards to measles. IF you look at the outbreak in 2014–2015 that started at the California theme park and ended up in 8 southwestern states. The number of adults that were infected with measles was over 50%, so were these current cases all isolation cases that were hospitalized or are we seeing measles with a dramatic impact in adults as well?

Dan Filardo (CDC): Our data so far this year shows about 1/4 of our cases have been in those over the age of 20. The age makeup of an outbreak depends on the population in which it occurs and depends on how likely they were to have either had measles as a child and therefore have some preexisting immunity, have been captured by a well-functioning vaccination system, and if they’re born in the U.S.We are finalizing an analysis of severity of disease by vaccination. We looked at our data since 2000 in terms of severe illness and severe complications or hospitalization related to measles. Rates are highest in those under one year (who are most at risk for severe disease and severe outcomes) and those under the age of five. There’s a sort of grace period in between age 5–19 where the complications, or the development of complications, and the hospitalization rates are lower. In those over age 20 they’re higher. Measles can be severe for adults. It can lead to hospitalizations and to severe complications like encephalitis and pneumonia.

 

Q: Of the cases, how many of them are in older adults and is the impact in older adults more dramatic?

Paul Offit (CHOP): My recollection from the data in the early days of measles was that usually they are about 10 times more likely to be hospitalized with pneumonia as an adult compared to if you had measles as a child. It was worse for adults. You could make the same argument for varicella-induced pneumonia. We had an outbreak of measles in Philadelphia this year, and it centered around the first case, which was a 7-month-old who came into the hospital whose mother had been both vaccinated and naturally infected but traveled to another country. The child was exposed there and then came back to the U.S. The child had a very unusual rash—not the usual measles rash which starts at the hairline spreads down to the face then trunk then then then arms and legs, congestion, cough, and Koplik’s spots. The rash was blotchy, and it was confirmed later as being measles. I think there was likely an attenuation of that child’s illness because of those passively-transferred antibodies from the mother, even seven months later. We asked the mother to please quarantine her child for about three weeks, but the next day she sent the child to the daycare center. Our initial reaction is that that puts everybody at risk, but there are a lot of people who don’t have the option of staying home for 2–3 weeks. We’re very bad at allowing people to have sick leave; that’s part of the infrastructure problem.

Dan Filardo (CDC): In terms of atypical rash, I completely agree with what Dr. Offit said that for those with (passively-transferred antibodies) who develop measles despite prior vaccination and despite prior immunity. Rarely do you see the absence of a rash, so it’s somewhat hard to know how that happens. People tend to not get tested for measles when they don’t have a rash so it becomes a circular issue identifying how often that might happen. Atypical appearance of rash certainly can occur and may be attenuated symptoms with much lower grade fever than you expect with measles in someone who’s unvaccinated or previously unprotected.

On the topic of maternal antibodies, I think it’s interesting that Dr. Offit mentioned that in the index case from that Philadelphia outbreak, the mother had measles as a child and we know that the duration of protection for an infant born to somebody who has had measles is much longer on average than for an infant born to a person who has been vaccinated against measles but has not had measles themselves. We think that the duration of those vertically transmitted antibodies is shorter than six months and sometimes as short as three or four months, so that’s a problem that you encounter. In the elimination setting, when few pregnant people have measles as a child, most of the infant’s immunity is vaccine derived, and they are unprotected until they get vaccinated. So, you really need a strong vaccination program to surround them to protect those infants in that elimination setting. You need strong vaccine requirements in daycares and other places where infants might get exposed.

On the topic of isolation, it is very challenging, and we understand that quarantine of high risk contacts is still really a mainstay of measles control because of how transmissible the disease is. The outbreak in Philadelphia really highlighted that. There was a person recommended to be quarantined, known to be unprotected and had a prolonged and close exposure to measles. This person then went to daycare, developed measles and exposed other unprotected children. That’s the worst-case scenario you want to avoid when attempting to control measles. We’ve heard a lot from local and state health departments especially in the post COVID-19 era the difficulty of implementing and recommending quarantine to people. But this is because of the transmissibility of measles and the fact that an infectious case in a closed setting like a school and daycare largely finds people who are unprotected just because of how transmissible the virus is. Most of the hospitalizations in adults that we’ve seen this year have been from isolation issues.

We’ve had only four cases so far reported this year in people over the age of 50.

Paul Offit (CHOP): In that 1991 outbreak, 600 of the cases and six of the deaths occurred in that religious community. About 900 of the cases and three of the deaths occurred in the surrounding community. The virus doesn’t recognize your religious beliefs, which is to say that they made a choice for other people. When we talk about individual rights or personal freedom out of autonomy, this is a contagious disease, you aren’t just deciding for yourself. That’s not okay.

L.J Tan (Immunize.org): Many adults don’t have documentation of MMR. Based on what you’ve said, does that mean that they should be recommending those adults receive a dose of MMR just to make sure they have a documented dose?

Dan Filardo (CDC): In the ACIP recommendations there is a line about birth year which states that if you were born before 1957 that person has presumptive evidence of immunity and that’s because prior to the introduction of measles vaccine it was expected that basically every child got measles, that there is immunity derived from getting measles and so is subsequently protected. We think it’s lifelong protection, and reinfection is limited to one or two case reports. So that immunity is lifelong for those born before 1957. I understand there’s concern about having the vaccine records. There’s sort of two paths forward, one would be to just get an MMR dose (there’s no harm really in getting an MMR dose if you are previously immune), the other option would be to talk to a healthcare provider and have a measles Ig test run because another acceptable proof or presumptive proof of immunity would be detectable measles Ig. A positive test is suggestive of either prior vaccination or prior exposure to the virus. For people without documentation of prior MMR and if that Ig test is either equivocal or negative, then it would be recommended that that person go on to get the MMR dose to really get up to date on those recommendations.

 

Q: Where is MMR vaccine covered for Medicare?

L.J Tan (Immunize.org): The vaccine is covered for adults on Medicare under Medicare Part D

 

Q: Can you speak to the access of care piece, particularly in the context of the Chicago outbreak which was an immigrant population that was being housed in the center?

Dan Filardo (CDC): I don’t want to speak for my colleagues that were on the ground, but I can share a little bit of my observation from the response. Chicago did a lot of work to make vaccination accessible, but vaccination uptake was really driven by a variety of things. They have provided more than 6,000 doses since the recognition of this outbreak, which was at the end of the first week of March. They have done an immense vaccine campaign in response to this outbreak, but I think this is potentially a call to action to all communities within the United States. It’s not just about providing the vaccine or physically having the vaccine, but about messaging with the community, outreaching, and making sure that they can come to a clinic, and if not, to attempt in whatever way to provide vaccination to where people can get it before an outbreak like this occurs.

Paul Offit (CHOP): The reason that you can eliminate measles from the United States and (we eliminated this most contagious disease by the year 2000) is that it’s a long incubation period disease, so really all you need is immunological memory which generally is long lived because there’s plenty of time for activation and differentiation of those memory cells. Memory T-cells prevent even mild infection, which is why you can eliminate measles. Those with a short incubation period like influenza, respiratory sensational virus, rotavirus, you’ll never eliminate them even if the whole world was vaccinated, and even if the viruses never evolve or mutate or create variance. People need to understand that when we talk about getting antibodies to determine whether you have immunity to measles that’s not completely fair, because you may not have circulating antibodies but still may have high frequencies of memory B-cells and T-cells that are not easily commercially measured. We don’t measure them, but generally, somebody like me who was naturally infected as a child, is protected against measles for the rest of their lives because of high frequencies of memory B-cells and T-cells. That needs to be made clear.

 

Q:  If you’re fully vaccinated what’s the best way to continue to improve your protection against measles?

Paul Offit (CHOP): This was a one-dose vaccine starting in 1963 and it became a two-dose vaccine in the early 1990s, so currently being fully vaccinated means you have two doses of vaccine. One dose provides roughly 93% protection and two doses provides roughly 97% protection so it is a remarkably effective vaccine. I think people are worried now because they’re reading a lot about these outbreaks, but again, where we are, compared to where we were (which is 3 to 4 million cases a year), is much lower. I wouldn’t quite panic yet. Two doses of vaccine put you in good shape and if you have already had the measles, you are in good shape.

Dan Filardo (CDC): Vaccination is key to control of measles. Try to encourage the people around you to recognize the importance of vaccination, especially for international travelers. We’re really trying to highlight that as a piece that sometimes gets missed in the conversation. 

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Announcements
  • The Summit is soliciting nominations for awardees for the 2024 NAIIS Immunization Excellence Awards. Nomination deadline is May 1. For information, visit: https://fs29.formsite.com/uI8uzs/2024NAIISAwards/index
  • Summit will host two webinars for its Virtual Flu days, May 16 and 23, to help partners plan for the respiratory virus season ahead of August, when the Summit’s in-person meeting will follow the National Immunization Conference (NIC). For information on these webinars and to register for one or BOTH, see: Setting the Stage for 2024–2025 Respiratory Virus Season.
  • The Summit in person meeting has been moved to August to accommodate the National Immunization Conference (NIC), which is being held in Atlanta, GA, on August 12–14. Register for NIC.
  • The Summit in person meeting, focusing on adult immunizations, will be held August 15 (full day) and August 16 (half day). Registration is being coordinated with the NIC registration and should be available soon.
  • The Summit workshop developed tools to address challenges in providing multiple adult vaccines along with COVID-19, flu, and RSV vaccines. See the Summit’s Operationalizing Adult Immunizations in the 2023 Fall Season and Beyond Workshopweb page for the deliverables.
  • There is a new zoom link for the 2024 Summit meetings. If you do not have the new link, please contact info@izsummitpartners.org.
  • If you have agenda items you are interested in sharing with the Summit, please tell us and we can add you to an upcoming call as a speaker or panelist. Contact information: info@izsummitpartners.org

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