Nav: Home

When is best time to get flu shot? Analysis compares scenarios

March 14, 2019

PITTSBURGH, March 14, 2019 - When flu season peaks after mid-winter, tens of thousands of influenza cases and hundreds of deaths can likely be avoided if older adults wait until October to get their flu immunization, a University of Pittsburgh School of Medicine analysis reveals in the April issue of the American Journal of Preventive Medicine.

The protection offered by the flu vaccine wanes as the season progresses, a previous study has shown, which indicates that waiting until closer to the start of flu season ensures greater immunity. However, if flu season arrives early or if delayed vaccination prompts more than one in 20 people who would otherwise be vaccinated to skip their flu shot, then the gains are negated, according to the new study, which is online now.

"There's controversy in the public health community over whether influenza vaccination should happen as soon as the vaccine becomes available in August, or if it's better to wait until later in the fall," said lead author Kenneth J. Smith, M.D., M.S., professor of medicine and clinical and translational science in Pitt's Division of General Internal Medicine. "What we've found is that it's a balancing act, but if a clinician believes a patient will return for vaccination in the fall, then our analysis shows that it is best if they advise that patient to wait."

Smith and his co-authors ran computer models to compare a "compressed" vaccination period that begins in October to the status quo, which typically begins in August, for people aged 65 or older. They focused on older adults because waning vaccine effectiveness is more of a threat to the elderly whose immune systems don't typically mount as strong of a defense to infections as younger people. Older adults also have higher early vaccination rates than younger adults.

Using data from the 2013-2014 and 2014-2015 flu seasons, the researchers forecast the number of cases, hospitalizations and deaths for compressed and status quo vaccination scenarios if the flu season had peaked in December, February or April - early, normal or late, respectively. "Peak" refers to the period when the greatest number of people are sick that season.

In the projections for the normal and late flu seasons, compressed vaccination saved as many as 258 lives and prevented up to 22,062 cases of flu, compared to status quo vaccination timing.

But if flu season peaked early, as it does in about one of every four seasons, the model projected that dozens to hundreds of older adults would die because they wouldn't have been vaccinated in time.

In addition, the team found that if more than 5.5 percent of older adults who defer vaccination ultimately don't get the flu shot, then compressed vaccination will be a failure and will prevent fewer influenza cases than status quo vaccination.

Smith says these findings can help clinicians determine when to offer their patients flu immunizations - if the patients have multiple appointments each year and will be in the office in the fall or if they are in a senior community where flu immunization is offered through a scheduled clinic, then waiting is likely advisable. But if a patient comes in only for an annual check-up and is unlikely to seek out the flu vaccine in the fall, or if offering vaccinations during a compressed window will put overwhelming strain on the clinic, then getting vaccinated when convenient - even if that's in August - is best.

"In all scenarios, simply getting vaccinated is the best way to avoid the flu," said Smith. "If the choice is between getting the influenza immunization early or not getting it at all, getting it early is definitely better."
-end-
Additional authors on this research are Glenson France, M.A., Mary Patricia Nowalk, Ph.D., Jonathan M. Raviotta, M.P.H., Angela Wateska, M.P.H., and Richard K. Zimmerman, M.D., M.P.H., all of Pitt; Jay DePasse, B.S., of Carnegie Mellon University; and Eunha Shim, Ph.D., of Soongsil University in South Korea.

This research was funded by National Institute of General Medical Sciences grant no. R01 GM111121.

To read this release online or share it, visit http://www.upmc.com/media/news/031419-smith-compressed-fluvax.

About the University of Pittsburgh School of Medicine

As one of the nation's leading academic centers for biomedical research, the University of Pittsburgh School of Medicine integrates advanced technology with basic science across a broad range of disciplines in a continuous quest to harness the power of new knowledge and improve the human condition. Driven mainly by the School of Medicine and its affiliates, Pitt has ranked among the top 10 recipients of funding from the National Institutes of Health since 1998. In rankings recently released by the National Science Foundation, Pitt ranked fifth among all American universities in total federal science and engineering research and development support.

Likewise, the School of Medicine is equally committed to advancing the quality and strength of its medical and graduate education programs, for which it is recognized as an innovative leader, and to training highly skilled, compassionate clinicians and creative scientists well-equipped to engage in world-class research. The School of Medicine is the academic partner of UPMC, which has collaborated with the University to raise the standard of medical excellence in Pittsburgh and to position health care as a driving force behind the region's economy. For more information about the School of Medicine, see http://www.medschool.pitt.edu.

http://www.upmc.com/media

Contact: Allison Hydzik
Office: 412-647-9975
Mobile: 412-559-2431
E-mail: HydzikAM@upmc.edu

Contact: Courtney Caprara
Office: 412-647-6190
Mobile: 412-592-8134
E-mail: CapraraCL@upmc.edu

University of Pittsburgh

Related Vaccination Articles:

Researchers develop microneedle patch for flu vaccination
A National Institutes of Health-funded study led by a team at the Georgia Institute of Technology and Emory University has shown that an influenza vaccine can produce robust immune responses and be administered safely with an experimental patch of dissolving microneedles.
Rotavirus vaccination in infants and young children
Rotaviruses (RV) are the commonest cause of diarrhea in infants and young children worldwide.
Industry and occupation affect flu vaccination coverage
Not surprisingly, healthcare workers are almost twice as likely to get flu vaccines as those in other occupations.
Child's vaccination data handily available via Kasvuseula service
Parents can now follow their tots' vaccinations via the Kasvuseula online service, which provides analytical data on the child's growth.
Foot-and-mouth crises to be averted with vaccination strategy
Future outbreaks of foot-and-mouth disease (FMD) can be controlled effectively and quickly with vaccinations -- saving millions of pounds and hundreds of thousands of livestock -- according to research by the University of Warwick.
HPV prevalence rates among US men, vaccination coverage
Human papillomavirus (HPV) infection is the most common sexually transmitted infection in the United States, as well as a cause of various cancers, and a new study published online by JAMA Oncology estimates the overall prevalence of genital HPV infection in men ages 18 to 59.
Anesthetic cream best for relieving vaccination pain in infants
For babies under age one year, lidocaine cream, combined with a small amount of sugar given by mouth and infant soothing, can help relieve pain from routine vaccinations, according to a study in Canadian Medical Association Journal.
Measles prevention -- how to pull the trigger for vaccination campaigns?
Routine vaccination has greatly reduced measles deaths in recent years, but very high vaccination coverage is needed to prevent disease outbreaks.
Using satellite images to better target vaccination
Vaccination campaigns can improve prevention and control of disease of outbreaks in the developing world by using satellite images to capture short-term changes in population size.
Maternal vaccination again influenza associated with protection for infants
How long does the protection from a mother's immunization against influenza during pregnancy last for infants after they are born?

Related Vaccination Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#SB2 2019 Science Birthday Minisode: Mary Golda Ross
Our second annual Science Birthday is here, and this year we celebrate the wonderful Mary Golda Ross, born 9 August 1908. She died in 2008 at age 99, but left a lasting mark on the science of rocketry and space exploration as an early woman in engineering, and one of the first Native Americans in engineering. Join Rachelle and Bethany for this very special birthday minisode celebrating Mary and her achievements. Thanks to our Patreons who make this show possible! Read more about Mary G. Ross: Interview with Mary Ross on Lash Publications International, by Laurel Sheppard Meet Mary Golda...