A: Peak influenza activity generally occurs in the Northern Hemisphere in January or February. Providers should continue vaccinating patients through spring, as long as there is continued circulation of influenza viruses and they have unexpired vaccine in stock and unvaccinated patients in their office.

Because influenza occurs in many areas of the world during April through September, vaccine should be given to travelers who missed vaccination in the preceding fall and winter. Another late season use of vaccine is for children younger than age 9 years who needed 2 doses of vaccine but failed to get their second dose early in the season. For each of these situations, vaccine can be given through the month of June since most injectable influenza vaccine has a June thirty expiration date.

A: A contraindication is a condition in a recipient that increases the risk for a serious adverse reaction to vaccination and is a condition under which vaccines should not be administered. In addition to contraindications found in prescribing information, ACIP may recommend against the use of a vaccine under certain conditions, such as a lack of data about use of a vaccine in a specific situation, such as pregnancy.

A precaution is a condition in a recipient that might increase the risk for a serious adverse reaction, might cause diagnostic confusion, or might compromise the ability of the vaccine to produce immunity. For example, not vaccinating a person who is moderately or severely acutely ill avoids diagnostic confusion between the underlying illness and side effects of vaccination. Vaccination may be deferred if a precaution is present, although a vaccination might be indicated in the presence of a precaution if the benefit of protection from the vaccine outweighs the risk for an adverse reaction.

Q: We frequently see patients who are febrile or have an acute illness and are due for vaccinations. We are uncertain if we should withhold the vaccines or not. What do you advise?

A: A “moderate or severe acute illness" is a precaution for administering any vaccine. A mild acute illness (such as diarrhea or mild upper respiratory tract infection) with or without fever is not a precaution, and vaccines may be given.

The concern in vaccinating someone with moderate or severe illness is that a fever following the vaccine could complicate management of the concurrent illness—it could be difficult to determine if the fever was from the vaccine or due to the concurrent illness. In deciding whether to vaccinate a patient with moderate or severe illness, the clinician needs to determine if deferring vaccination will increase the patient’s risk of vaccine-preventable diseases, as is the case if the patient is unlikely to return for vaccination or to seek vaccination elsewhere.

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A: CDC has used the term "fully vaccinated" to refer to people who have completed a primary COVID-19 vaccine series. CDC uses the term “up to date" (UTD) to refer to a person who has received all doses recommended for their age and health status. With the exception of children age 6 months through 4 years who have completed a 3-dose primary series with Pfizer-BioNTech COVID-19 Vaccine, for whom no booster dose is recommended, all other people age 6 months and older are considered UTD if they have completed a primary series and have received a bivalent COVID-19 booster dose. The definition of up-to-date vaccination of each age group is available here: www.cdc.gov/vaccines/covid-19/downloads/COVID-19-immunization-schedule-ages-6months-older.pdf.

A: Yes, but only in limited circumstances. Patients age 18 years or older who have completed any COVID-19 vaccine primary series, but who have never received a booster dose, may be offered a single Novavax monovalent COVID-19 vaccine as a booster dose under one of the following conditions: (1) the recommended bivalent mRNA vaccine is contraindicated, or (2) the patient refuses the recommended bivalent mRNA vaccine booster dose (or it is unavailable) and would not otherwise be vaccinated. The Novavax monovalent vaccine is not authorized for use as a booster dose in a person who has received one or more COVID-19 vaccine booster doses in the past.

A: CDC states that no additional medical documentation is required before vaccination. People may simply affirm that they are moderately or severely immunocompromised and receive COVID-19 vaccine doses wherever vaccines are offered. Vaccinators should not deny COVID-19 vaccination to a person due to lack of documentation.

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A: No. The series should not be restarted. Continue the series from where you left off.

A: Do nothing. Data show that vaccine-induced anti-HBs levels might decline over time; however, immune memory (anamnestic anti-HBs response) remains intact following immunization. People with anti-HBs concentrations that decline to less than 10 mIU/mL are still protected against HBV infection. For healthcare professionals with normal immune status who have demonstrated adequate anti-HBs (at least 10 mIU/ mL) following full vaccination, booster doses of vaccine or periodic anti-HBs testing are not recommended.

A: Yes. Adolescents and adults who started the HPV vaccine series prior to the 15th birthday and who are not immunocompromised are considered to be adequately vaccinated with just one additional dose of HPV vaccine.