National vaccine experts on Thursday approved tweaks to flu vaccine policies, a reduction in rabies vaccine doses for children and a new dengue vaccine for children in endemic areas.
The Centers for Disease Control and Prevention's (CDC’s) Advisory Committee on Immunization Practices (ACIP) approved each of the vaccine changes with 14-0 votes, sending them to the CDC director for final approval and publication in Morbidity and Mortality Weekly Report.
The CDC’s proposed 2021-’22 influenza policy continues to recommend everyone ages 6 months and older get vaccinated but will incorporate several changes regarding coadministration with COVID-19 vaccines, timing, available vaccines and contraindications.
The policy would allow coadministration of influenza vaccines with COVID-19 vaccines, consistent with the practices ACIP approved last month. While all members approved, several stressed the importance of getting more data on coadministration in the coming months. Yvonne A. Maldonado, M.D., FAAP, chair of the AAP Committee on Infectious Diseases (COID), noted the AAP is working with the CDC and other partners in ensuring COVID-19 vaccines are safe and effective for children.
“There are unknowns about COVID-19, but we do know this disease is deadly in children,” she said. “ … We continue to believe that the best way to deal with COVID as well as the other diseases that we know affect children and adolescents is to make sure everybody is as up to date on all of their (immunizations) as possible.”
The flu policy also would provide specific information on when people should get vaccinated. For children, this ideally would be by the end of October.
“This is because there are fewer data reflecting the significance of waning immunity among children and also concerns about this population missing vaccinations,” said Lisa Grohskopf, M.D., M.P.H., a medical officer in the CDC’s Influenza Division.
Adults who are not pregnant should avoid vaccination in July and August due to the potential for waning immunity. However, those who are in the third trimester of pregnancy should consider getting vaccinated as soon as the vaccine becomes available to protect their infants.
The 2021-’22 influenza season will be the first in which all available vaccines are quadrivalent. The Flucelvax vaccine from Seqirus will be available for children as young as age 2 instead of age 4, a change approved by the Food and Drug Administration (FDA) in March. A randomized trial conducted among more than 4,000 children ages 2-17 found efficacy of 55% against any influenza and 63% against matched strains.
Another change to the policy is an addition to the contraindications and precautions table regarding allergic reactions for influenza vaccines. It will include a new statement that calls out cell-based inactivated influenza vaccines and notes that they are contraindicated for people with a history of severe allergic reaction to these vaccines or any component of them. Precautions should be taken for those with moderate or severe acute illness, history of Guillain- Barré syndrome within six weeks of an influenza vaccine or history of severe allergic reactions to a previous dose of any other flu vaccine. This last precaution also was added to the precautions list for recombinant influenza vaccines.
Children who need rabies pre-exposure prophylaxis (PrEP) will be able to do so with a two-dose vaccine series instead of three doses, under new recommendations approved Thursday. The doses will be administered seven days apart in immunocompetent children.
In addition, children with a sustained and elevated risk of rabies exposure will be able to get a booster dose of vaccine as an alternative to a titer check. The booster should be administered at least 21 days and no later than three years after the initial PrEP series.
Agam Rao, M.D., the CDC lead for ACIP’s rabies work group, noted children’s inquisitive nature and short statue put them at increased risk of animal bites, especially to the face and neck. A study of 190 children found 100% had antibody titers of at least 0.5 IU/mL with a two-dose series. ACIP members agreed the shorter PrEP series would be more convenient and cost effective while still providing protection from rabies.
“When you have such huge stakes, it makes it harder to reduce a vaccine schedule,” said ACIP member Sarah S. Long, M.D., FAAP, professor of pediatrics at Drexel University College of Medicine. “We’re frequently accused of only adding and never taking away, but with careful data that was gathered … I’m very comfortable with this and I am very happy once in a while we can do this.”
Children in areas like Puerto Rico where dengue is endemic may be able to get vaccinated soon. ACIP members gave the green light to using Dengvaxia from Sanofi Pasteur Inc. for routine vaccination in children ages 9-16 years who live in endemic areas and have laboratory confirmation of a previous dengue infection.
Dengvaxia was licensed by the FDA in 2019 to prevent four types of dengue, a virus transmitted by mosquitoes. It is given in a series of three doses six months apart and has an efficacy of 82% for symptomatic dengue infection.
Vaccine administration will be complicated because giving the vaccine to children who have never had dengue puts them at increased risk of severe dengue infection. Therefore, children will need to be screened before vaccination using tests with high levels of sensitivity and specificity to confirm previous infections. The CDC said it has identified several such tests that meet the criteria.
Dr. Maldonado said the COID has been impressed with the progress made on planning for administration of the vaccine over the past several years.
“I understand the risks sound uncomfortable but really the risks here are extremely manageable, albeit there will be a number of administrative obstacles to move through,” she said.