A summary of presentations from the weekly Summit partner webinars

May 5, 2022 – The latest Summit summary

COVID-19 Vaccines: Second Booster and the Future of COVID-19 Vaccine Boosters Sarah Meyer (CDC)

Sarah Meyer, MD, MPH, Chief Medical Officer (Acting), NCIRD, CDC gave a presentation on the updated CDC guidance for the second COVID-19 booster and the future of COVID-19 vaccine boosters. VIEW PRESENTATION SLIDES.

Current COVID-19 Vaccine Recommendations

  • A COVID-19 primary series is recommended for everyone ages 5 through 11 years
  • A COVID-19 booster dose is recommended for everyone age ≥12
  • In most situations, an mRNA COVID-19 vaccine is preferred over the Janssen COVID-19 Vaccine for primary and booster dose

After the FDA took regulatory action on March 29, the CDC updated its guidance to allow some people to receive a second booster dose using an mRNA COVID-19 vaccine at least four months after their first booster dose. The people who are eligible for the second booster are individuals age ≥50, individuals ≥12 who are moderately or severely immunocompromised, and individuals ≥18 who received the Janssen for the primary and booster dose. The considerations are summarized on CDC’s COVID-19 Vaccine Boosters web page.

Receiving the first booster dose is very important for protection against infection and death due to COVID-19, particularly with the Omicron variant. Unvaccinated people age ≥12 had a three-fold higher risk of testing positive for COVID-19 (data from February 2022) and a two-fold higher risk i(data from March 2022), compared to those vaccinated with a primary series and a booster dose. Unvaccinated people had a twenty-fold higher risk of dying from COVID-19 compared to vaccinated people. The risk of severe disease or death decreases with the booster dose.    See: CDC COVID Data Tracker: Rates by Vaccine Status (Accessed 4/19/22)

Researchers looked at vaccine effectiveness (VE) against COVID-19-associated hospitalizations in adults during the Omicron wave, which allowed for the comparison in VE based on vaccine type of the booster dose. They found that people who had one Janssen vaccine without a booster had the lowest VE at 37%, people who had the Janssen primary vaccine and a Janssen booster had 64% VE, those who had a Jansen primary vaccine and an mRNA booster had a VE at 78%, and those who had three doses of an mRNA vaccine had the highest VE at 90%. This data was used to update the guidance that people who received two doses of Janssen could get a second booster with an mRNA vaccine.    See: MMWR: Effectiveness of Homologous and Heterologous COVID-19 Booster Doses Following 1 Ad.26.COV2.S (Janssen [Johnson & Johnson]) Vaccine Dose against COVID-19–Associated Emergency Department and Urgent Care Encounters and Hospitalizations among Adults—Vision Ne(4/1/22)

A study looked at the VE against hospitalization in adults age ≥50 who received three doses of an mRNA vaccine from December of 2021 to March of 22 based on immunocompromise status. The findings show that early after completion of the third dose, people who are not immunocompromised have a high VE at against hospitalization, and this remains high but wanes over time from 93% to 84%. For those who are immunocompromised, after the third mRNA dose, VE against hospitalization was at 81%, however waned more quickly. At 120–170 days post third dose, there was only 49% VE against hospitalization. This data helped to inform the CDC to include a second booster to people who are age ≥50 and immunocompromised in its booster guidance.

A study out of Israel looked at the effectiveness of the fourth dose of the COVID-19 mRNA vaccine against Omicron among people ≥60. Early this year, they began administering a fourth dose of Pfizer-BioNTech mRNA vaccine in those ≥60 who had a third dose of the vaccine at least four months prior. They followed the individuals from January 2 through March for confirmed infection and severe illness. What they found is that the fourth dose is estimated to prevent an additional 3–4 cases of severe disease per 100,000 person-days compared to three doses. Protection against confirmed infection was short-lived, however protection against severe illness remained steady through the end of the observation period.   See: NEJM: Protection by a Fourth Dose of BNT162b2 against Omicron in Israel

Vaccine effectiveness of a 4th dose against Omicron in people age ≥60 in a large healthcare organization was 70% against hospitalization and 76% for death.   See: NEJM: Fourth Dose of BNT162b2 mRNA COVID-19 (4/28/22)

Considerations for eligible people on getting a second booster dose as soon as possible include:

  • People with certain underlying medical conditions that increase the risk of severe COVID-19 illness
  • People who are moderate or severely immunocompromised
  • People living with someone who is immunocompromised, at increased risk for severe disease, or who cannot be vaccinated due to age or contraindication
  • People with increased risk of exposure to SARS-CoV-2 through occupational, institutional, or other activities
  • People living or working in an area where the COVID-19 community level is medium or high

Considerations for eligible people on waiting to receive a second booster dose include:

  • People with recent SARS-CoV-2 infection withing the past three months
  • People hesitant about getting another recommended booster dose in the future, as a booster dose may be more important in the fall and/or if a variant-specific vaccines is needed

CDC recommends that everyone get up to date on their COVID-19 vaccines, which means that a person has received all the recommended doses in their primary series and a booster dose, when eligible. The receipt of a second booster dose is not necessary to be considered up to date at this time.

COVID-19 epidemiology is unpredictable right now, as it does not have a defined season and it’s difficult to predict the timing of future surges. A booster dose may be needed in the fall prior to next winter. Planning for future doses of COVID-19 will require continued evaluation of COVID-19 epidemiology and VE, including the impact of both time, variants, and the ability of doses to improve protections. The evolution of COVID-19 vaccines will be important as the SARS-CoV-2 virus evolves. This may include changes in the strains included in the vaccines as well as vaccine platform.

FDA and CDC will continue to partner for future discussions. The ACIP will continue to review additional data on COVID-19 epidemiology, genomic surveillance, and VE. Manufactured data on safety, immunogenicity, and possible efficacy of variant-specific vaccines will also be monitored. In addition, further discussions around feasibility, implementation, and balance of benefit and risks by age group and population will be needed to inform the timing and populations for future doses of COVID-19 vaccines.


Flu Surveillance Update – Alicia Budd (CDC)

Alicia Budd, MPH, Influenza Division, CDC, gave an update on CDC’s flu surveillance from FluVIew through the week ending on April 23, 2022 (week 16). VIEW PRESENTATION SLIDES.

Influenza Virologic Surveillance – U.S., 10/3/21–4/23/22:

Flu activity measured by percent of specimens tested positive in clinical labs has been increasing every week since early February until last week. There was a dip in percent positive cases two weeks ago, however that was most likely due to missing data from labs. There are several regions where the activity is continuing to increase: region 4 which is the southeast, and region ten which is the pacific northwest and Alaska.

The U.S still has predominately influenza A H3N2 viruses belonging to the 3C.2a1b clade and the 2a.2 subclade, which is what has been circulating all season. Influenza A H3N2 viruses are found to be not antigenically similar to the vaccine viruses. Of the over 1,100 viruses tested, only one has reduced antiviral resistance, which is to the drug Baloxavir.

Outpatient Visits for Respiratory Illness, Reported by the U.S. Outpatient Influenza-like Illness Surveillance Network (ILINet): Influenza-like illness (ILI) refers to someone who has a fever and cough or sore throat and could be caused by a number of respiratory viruses, including flu and SARS-CoV-2. The percent of visits continues to increase but remains below the national baseline. The increase is being driven primarily by children and young adults.

ILI Activity Level, Determined by Data Reported to ILINet, Week ending April 23, 2022 (Week 16): During week 16 there have been a few areas with increased activity. These areas are all seeing increases in flu but also increases in other respiratory viruses, as well.

Percent of Long-Term Care Facilities (LTCF) with at least One Confirmed Influenza Case among Residents, Reported to CDC’s National Healthcare Safety Network (NHSN), National Summary, 10/4/21–4/23/22:  The number of LTCF reporting at least one flu positive case among their residents declined slightly this past week after a very slow increase for the last couple of months.

Influenza hospitalizations in the U.S.: HHS Protect shows the number of new admissions to hospitals that have a positive influenza test, which has been increasing for 12 weeks in a row. The cumulative influenza-associated hospitalization rate from FluServNet shows that flu activity is tracking higher than the 2011–12 season, which was the mildest pre-COVID-19 flu season since the FLuServNet system began in 2005. Hospitalizations are low, however continuing to increase.

Influenza-related mortality data, U.S.: The percentage of death certificates that list pneumonia, influenza, or COVID-19 (PIC) as the cause of death is holding stable and hovering right around the epidemic threshold for the past three weeks. There have been 23 pediatric deaths this season, all of which were subtyped, tested positive for influenza A H3N2 viruses.

International Influenza Activity, Number of Influenza Positives Reported to WHO’s FluNet, 10/2018–4/23/22: Flu positive activity reported to WHO shows that influenza A H3N2 is predominate worldwide except in China where influenza B (Victoria) is the dominate virus.

Additional Information

Influenza Activity

Other Respiratory Virus Activity

Highly Pathogenic Avian Influenza (HPAI) A(H5N1): Current Situation in the U.S. as of May 4, 2022

There have been increases in the number of states with HPAI A(H5N1) detected in birds. There are now 34 states with H5N1 detected in wild birds and 32 with HPAI A(H5N1) detected in commercial poultry/backyard flocks. CDC has monitored around 2,600 people who have been exposed since the start of the year, this includes 70 people with symptoms. CDC has tested over 80 people for the virus.

There has been one person with detected HPAI A(H5N1). This person had close, prolonged exposure to infected birds and their environment. The only reported symptom was fatigue, which resolved after three days. The specimen was collected and tested positive on April 20, and then tested negative six days later. This is an isolated incidence and there has been no known human-to-human transmission. With this case, it is unclear if there may have been transient nasal contamination or if this was an actual infection. There may be no way to know that for sure, so the CDC errored on the side of caution and isolated the patient and monitored close contacts.

The identification of HPAI A(H5N1) in a person is not surprising with the amount of human contact with birds. However, this does not change the overall low risk to the general population who does not work with or handle birds.

Further information:




If the community you live in moves from low COVID-19 risk to medium or high risk, do you now become eligible for the fourth booster dose even if you do not fall into the eligible groups?

Sarah Meyer

The community is a factor but the considerations only apply to the people that fall into the considerations for the fourth dose.



Is there any guidance on the fourth dose for pregnant women?

Sarah Meyer

Pregnant women are not currently called out in the guidance for the fourth dose. They must fall into one of the eligible categories.



There are a number of VRBPAC meetings scheduled in June for COVID-19 boosters. Can we expect the same for ACIP meetings?

Sarah Meyer

If FDA issues new or updated EUAs for any of the vaccines, then we would expect ACIP to meet shortly after.



If you received an mRNA vaccine and then Janssen for a second dose is that considered a booster?

Sarah Meyer

If someone had an mRNA vaccine but not a second and instead got the Janssen vaccine, in the guidance we consider that they had a Janssen primary series since Janssen was completed and not the mRNA series. We don’t consider that a booster. If someone had two mRNA vaccines and a Janssen booster they would be considered up to date with the booster.



Is there any data on the relationship of VE and natural immunity from COVID-19 infection?

Sarah Meyer

There has been a lot published on this lately. The people who have had the infection and the vaccination are shown to have lower risk of infection or re-infection. We always want to highlight that it is still very important to get vaccinated even if you have had prior infection. The vaccine will offer significant protection against reinfection. It’s unclear the level of protection one variant will have with another so that’s why we still get vaccinated. It’s the safest way to protect yourself.



If you get vaccinated and you develop mild COVID-19, is there data that suggests you are less likely to develop long COVID-19?

Sarah Meyer

There are a couple of studies that show people who have been vaccinated and get COVID-19 have a 50% lower chance of developing long VOCID-19 after infection. This is a new area of study.



Is the interval between the Janssen booster dose less than if it was an mRNA vaccine booster?

Sarah Meyer

The first booster dose after Janssen is at two months. From the mRNA vaccine primary series to the mRNA booster is five months. All people who have gotten a booster and are eligible for the fourth must wait four months no matter which vaccine booster was given previously.



What can you tell us about HPAI A(H5N1) testing?

Alicia Budd

Public health labs have test kits that have been there all along to test for H5. The kit works with this particular virus. Before running the H5 test, if someone has symptoms they will be given a seasonal flu test and a COVID-19 test before they give the H5 test. If clinicians come in contact with someone they suspect might have avian flu, they need to contact their health department.



Any ideas on why the flu incidence was so low this year? Is it COVID-19 competition, continued protection, less travel, working from home, etc.?

Alicia Budd

It could be all or any of those things. Life is getting much more back to pre-COVID-19 normal but this is also a new normal where there is still less interaction. A lot of mask mandates have been dropped, but many still chose to wear them. Some flu seasons have been mild pre-COVID-19, so there is always general variability. It’s certainly multifactorial.




  1. Meeting date change! The 2022 Influenza Vaccine meeting, What’s Up with Flu in ’22! Surveillance, Vaccines, Policy, and Communications Last Year and Next, will be held virtually on May 20, 2022, from 2:00–4:45 p.m. (ET). Pre-meeting registration is required by 5:00 p.m. (PT)/8:00 p.m. (ET) on May 18, 2022, to attend. For more information and to register, visit: https://www.izsummitpartners.org/2022-naiis/. The adult component of the meeting may be in-person and the tentative date for this meeting will be the first week of November––November 1–3.
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