Influenza key points

Healthcare providers and local public health departments are instrumental in preventing and controlling the spread of influenza in Massachusetts. Here are some important updates for this year:

Table of Contents

2019-2020 recommendation highlights

  • The 2018-2019 influenza season in the United States was moderately severe, with two waves of influenza A activity.  Influenza A H1N1 predominated from October 2018 to mid-February 2019, and influenza A H3N2 predominated from mid-February through mid-May.  The flu season lasted 21 weeks, making it the longest season in 10 years.  As of August 24, 2019, a total of 129 pediatric deaths had been reported to Centers for Disease Control and Prevention (CDC) during the 2019-2020 season.
  • Influenza vaccines for the 2019-2020 season have been updated to better match the circulating viruses (the A/H1N1 and influenza A/H3N2 components have been updated).
  • The CDC and its Advisory Committee on Immunization Practices (ACIP) recommend annual influenza vaccination for everyone 6 months of age and older with any licensed, influenza vaccine that is otherwise appropriate for the person’s age and health status. 
    • There are many different vaccination choices, including the quadrivalent inactivated influenza vaccines (IIV4s); quadrivalent recombinant influenza vaccine (RIV4) and quadrivalent live attenuated influenza vaccine (LAIV4).
    • High-dose inactivated influenza vaccine (HD-IIV3) and adjuvanted inactivated influenza vaccine (aIIV3) will be available in trivalent formulations for those 65 years and older.

For more information on this year’s flu recommendations:

Influenza key points

Vaccine viruses included in the 2019–20 U.S. influenza trivalent vaccines will be:

  • an A/ Brisbane/02/2018 (H1N1)pdm09–like virus (Updated);
  • an A/ Kansas/14/2017-like (H3N2)-like virus, (Updated); and
  • a B/Colorado/06/2017–like virus (Victoria lineage).

Quadrivalent influenza vaccines will contain these three viruses and an additional influenza B vaccine virus:

  • a B/Phuket/3073/2013–like virus (Yamagata lineage).

New formulations and licensure changes


FDA lowered the minimum age for Afluria Quadrivalent (IIV4) from ≥18 years to 6 months of age.  Afluria is now approved as a 0.25 mL dose for everyone 6-35 months of age and 0.5 mL for all persons 3 years of age.


The FDA approved a change in the dose volume for Fluzone Quadrivalent.  Previously, the dose volume for Fluzone Quadrivalent for children 6-35 months was 0.25 mL.  Now children in this age group may receive either 0.25 mL or 0.5 mL.  No preference is expressed for one dose volume over the other for children in this young age group.  Persons aged 3 years should receive the 0.5 mL dose.

Guidance for the Use of Influenza Vaccine in Children 6-35 Months of Age

There are now several influenza vaccine options for children 6-35 months of age.  Remember, the dose volumes for these formulations can differ.  Children in this age group may receive:

  • 0.25 mL of Afluria Quadrivalent; or
  • 0.5 mL of Fluarix Quadrivalent; or
  • 0.5 mL of FluLaval Quadrivalent; or
  • Either 0.25 mL or 0.5 mL dose of Fluzone Quadrivalent.

Care should be taken to administer the correct dose volume for age and formulation for each dose administered in this age group. 

Please Note: Children 6 months through 8 years who are receiving influenza vaccine for the 1st time or who have only ever received 1 dose of influenza vaccine before July 1, 2019, will need 2 doses (of the appropriate dose volume for age and formulation) separated by >4 weeks.  The two doses do not need to be the same influenza vaccine product.

Children 6 months through 8 years who have received 2 doses of influenza vaccine before July 1, 2019 (doses do not need to have been received during the same or consecutive seasons), only need 1 dose of influenza vaccine this season.

Influenza disease burden

The burden of disease is great. CDC estimates that influenza has resulted in between 9 million and 36 million illnesses, between 140,000 and 710,000 hospitalizations and between 12,000 and 56,000 deaths annually since 2010.

CDC now posts preliminary estimates of the influenza disease burden.

The good news is this year’s influenza vaccines have been updated to better match circulating viruses.

Your strong recommendation is important!

A health care provider’s strong recommendation is a critical factor affecting whether your patent gets influenza vaccine. Patients listen to providers when providers strongly recommend vaccination.

  • There are many misconceptions about flu vaccine.  Flu vaccine is recommended for everyone 6 months of age and older who do not have contraindications.  While some flu formulations are not recommended for some patients and some patients should not receive flu vaccine at all, this is uncommon.  For more guidance on contraindications and precautions for influenza vaccine, please see Table 2 on page 3 and pages 12-14 in the 2019-2020 ACIP Influenza Recommendations.

Below are and links to the latest information and data that might inform your conversations with patients in the upcoming months:

For more information on questions and answers related to this flu season, please see the General information about flu page.

MDPH resources and documents

Vaccine supply

MDPH universally provides influenza vaccine, as well as other routinely recommended vaccines, to all children through 18 years of age. MDPH only provides influenza vaccine for uninsured adults seen at public sites. For more information on state-supplied vaccine, please see the Vaccine Management page. MDPH created a table outlining the current state-supplied influenza formulations to ensure you are using the age-appropriate formulation and dose for the person you are vaccinating.

Information about the national vaccine supply can be found at CDC’s Seasonal Influenza Vaccine Supply & Distribution website.

When to vaccinate

Optimally, vaccination should occur before the onset of influenza activity in the community. CDC recommends vaccination by the end of October, if possible. To avoid missed opportunities for vaccination, providers should offer vaccination during routine health care visits and hospitalizations.  Vaccination efforts should continue into the winter months and throughout the season because duration of the influenza season varies and influenza activity might not occur in certain communities until February or March. In New England, flu activity usually lasts until April and May.

Safe influenza vaccine administration

When you “know the site and get it right,” you can help prevent one type of vaccine administration error—shoulder injuries such as deltoid bursitis—generally caused when vaccines are injected high on the shoulder and the needle enters a shoulder bursa. This is an error reported to occur mostly among adults. CDC provides comprehensive vaccine administration resources on their Vaccine Administration website.

Vaccine information statement



Infectious Disease Division (617) 983-6550
Urgent calls and infectious disease reporting (617) 983–6800
Laboratory Sciences Division (617) 983–6201


Infectious Disease Division (617) 983–6925
Laboratory Sciences Division (617) 983–6210


State Public Health Laboratory
305 South Street
Jamaica Plain, MA 02130