• ACIP Recommends Preexposure Ebola Virus Vaccine

    Committee Hears Updates on Influenza, COVID-19

    During the Feb. 26-27 meeting of the CDC's Advisory Committee on Immunization Practices, the group voted to recommend a preexposure vaccine against Ebola virus for adults.

    Woman receiving vaccine

    AAFP liaison to the ACIP Pamela Rockwell, D.O., of Ann Arbor, Mich., told AAFP News other business conducted during the meeting included receiving updates on influenza activity, which remains relatively high in the United States, and on the incredibly fluid COVID-19 outbreak and the federal government's preparations for a possible pandemic.

    Ebola Vaccine

    In a unanimous vote, the ACIP recommended preexposure vaccination against Ebola using the live attenuated recombinant vesicular stomatitis virus vaccine (rVSV-ZEBOV; Ervebo) for U.S. adults 18 or older who are at potential risk for exposure to the virus and

    • are responding to an outbreak of Ebola virus disease,
    • work as health care personnel at federally designated Ebola treatment centers in the United States or
    • work as laboratorians or other staff at Biosafety Level 4 facilities. 

    Approved by the FDA in December, the single-dose vaccine is administered intramuscularly. When used in a ring vaccination strategy, rVSV-ZEBOV has 100% vaccine efficacy, Rockwell said.

    On Feb. 12, the World Health Organization agreed that the ongoing Ebola virus disease outbreak in the Democratic Republic of the Congo constituted a "public health emergency of international concern."  

    EVD is deadly if it's untreated, with 70%-90% mortality, Rockwell said. However, mortality can be as low as 40% with early supportive treatment.

    Transmitted through contact with bodily fluids, signs and symptoms of EVD include fever, severe headache, severe fatigue, muscle and joint pain, bleeding (internal and external), abdominal pain, rash, diarrhea and vomiting.

    Story Highlights

    Zaire ebolavirus, which is responsible for the majority of reported EVD outbreaks, has infected more than 31,000 people and caused 12,000 deaths.

    Rockwell noted that the recommended Ebola vaccine cannot cause Ebola virus infection and protects only against the Zaire viral species.

    The committee's Ebola Virus Vaccine Work Group conducted a GRADE (Grading of Recommendations Assessment, Development and Evaluation) evidence review for preexposure rVSV-ZEBOV vaccination for healthy, nonpregnant, nonlactating patients 18 or older in the U.S. population who are at potential occupational risk for exposure to Ebola virus.

    Work group members said they recommended vaccination for these groups because of several factors:

    • documented protective efficacy of the vaccine in preventing symptomatic EVD;
    • high severity of illness in infected individuals;
    • high transmissibility of the virus;
    • EVD-related sequelae in survivors;
    • lack of an FDA-approved treatment for EVD; and
    • an acceptable safety profile, with rare serious adverse events reported during the GRADE analysis.

    As always, ACIP recommendations aren't considered final until they have been approved by the CDC and published in the agency's Morbidity and Mortality Weekly Report.

    COVID-19 Update

    Nancy Messonnier, M.D., director of the CDC's National Center for Immunization and Respiratory Diseases, provided an update on COVID-19, the disease caused by the coronavirus SARS-CoV-2.

    "She said that the public, communities, workplaces and schools need to be ready for a coronavirus outbreak," Rockwell said.

    Messonnier explained that there are seven human coronaviruses, which cause respiratory illness that is spread through respiratory droplets and possibly also by touching surfaces contaminated with the virus. These infections can be contracted year-round but usually occur in the fall and winter.

    Recommendations to prevent the highly transmissible infection, she said, continue to include basics such as

    • frequent, thorough hand-washing;
    • avoiding touching the eyes, nose and mouth;
    • avoiding close contact with sick people; and
    • staying home when sick.

    No antiviral treatment for COVID-19 is currently available, said Rockwell, only supportive treatment. She expressed concerned about the lack of readily available coronavirus testing kits, which the CDC is actively trying to remedy.

    "If you can't test people, then you also don't know how many cases there are," she said.

    It's also unclear whether other health factors raise the risk for infection, Rockwell added. "I don't know if having things like asthma, or if you're a smoker, makes you more susceptible. Nobody really knows those things yet."

    The AAFP continues to collect all information about the COVID-19 outbreak that is pertinent to family physicians in one place; be sure to bookmark it so you can check back for the latest news.

    Influenza Vaccine

    The Influenza Vaccine Work Group reported surveillance data shared in a Feb. 21 CDC Morbidity and Mortality Weekly Report that said the 2019-2020 influenza season began early, with predominantly influenza B/Victoria virus circulation. This was followed by increasing A(H1N1)pdm09 virus activity, and detection of both viruses is ongoing.

    "The influenza rate is still high," Rockwell said, "so we should still recommend the flu vaccine to patients."

    The work group also discussed a study that compared trivalent inactivated adjuvanted influenza vaccine (aIIV3; Fluad) with the trivalent high-dose inactivated influenza vaccine (HD-IIV3; Fluzone) in older adults and related instances of injection site pain and serious adverse events.

    Patients ages 65-79 and those 80 and older were given the two types of flu shots; the proportion of participants with moderate-to-severe injection-site pain was not higher after aIIV3 than HD-IIV3.

    There also were no vaccine-related serious adverse events or adverse events of clinical interest; short-term postvaccination health-related quality of life was not affected by either vaccine, Rockwell said.

    Down the road, she added, a systematic review/meta-analysis comparing influenza vaccine use in older adults is in the works, with the goal of determining whether relative benefits and harms of HD-IIV3, aIIV3 and recombinant influenza vaccine compared to other flu vaccines favor use of any one over the others.

    "In my community, most physicians are recommending most older adults get the high-dose HD-IIV3 Fluzone," she said. "This study will compare which one works better."

    Additional Topics

    Family physicians with immunization questions are invited to visit the ACIP's General Best Practice Guidelines for Immunization. Rockwell noted that errata and updates to this information were added Feb. 21.

    Some good news shared at the meeting was that Merck plans to begin distributing pediatric monovalent hepatitis B vaccine on March 9, with a company representative saying that available supply should be sufficient to meet overall demand, Rockwell said.

    Coming Next

    During the June ACIP meeting, according to Rockwell, the Rabies Vaccines Work Group plans to present its GRADE analysis and evidence.

    A study is in the works to see if a two-dose vaccine series is sufficient for the general U.S. population, which is at lower risk for rabies, or if there is a need for a booster for those at continuous risk, she said.

    There also is a plan to analyze how international rabies vaccines (given intradermally) perform compared to the U.S. vaccine (given intramuscularly).

    Finally, the Hepatitis Vaccines Work Group is planning to update its recommendations for hepatitis B vaccination for adults.

    Rockwell, who is a member of the work group, said discussion may focus on cost-effectiveness of the HepB vaccine. Specifically, the group might consider whether a routine universal HepB vaccination strategy (two-dose and three-dose schedules) should be used for adults rather than the current risk-based vaccination strategy.

    "We're going to look at all of the data to see if it would be cost-effective and good for the country for all adults to get HepB vaccine, whether you are in a high-risk group (e.g., have chronic liver disease, are a health care worker, have HIV or diabetes) or not," Rockwell said.