Flu-COVID 'Collision' Expected This Fall, Health Experts Warn

Kenneth J. Terry, MA

June 23, 2020

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

Public health and infectious disease experts warn that the United States needs to increase its influenza vaccination rate substantially this fall to mitigate a potentially deadly confluence of seasonal influenza with an anticipated second wave of COVID-19.

"When you have a collision of these two things happening at the same time, I think we're going to be in real trouble," Rochelle Walensky, MD, chief of the infectious diseases division at Massachusetts General Hospital, Boston, told Medscape Medical News

Walensky noted that about 45% to 50% of people get a flu vaccine in any given flu season. While a COVID vaccine is also needed, she said, increased uptake of the flu vaccine is sorely needed. "We need to do a massive vaccine campaign because that's something we can do something about in terms of prevention," she noted.

"High vaccine coverage would reduce influenza-related mortality, while also helping to preserve the capacity and function of the health system during circulation of influenza viruses and severe acute respiratory syndrome coronavirus 2," writes Lawrence O. Gostin, JD, a professor at Georgetown University's O'Neill Institute for National and Global Health Law, Washington, DC, and Daniel A. Salmon, MD, of the Institute for Vaccine Safety at Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, in a recent JAMA Viewpoint.

Gostin told Medscape Medical News that a bad flu outbreak this year "would be really ruinous for the healthcare system. If we continue to have those COVID spikes as a second wave, there would probably be 50% or 100% more hospitalizations on top of those from the flu."

In an editorial in Science Magazine, Edward A. Belongia, MD, director of the Center for Clinical Epidemiology and Population Health at the Marshfield Clinic Research Institute, Wisconsin, and Michael T. Osterholm, PhD, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, Minneapolis, write: "The stress on hospitals will be greatest if the COVID-19 and influenza epidemics overlap and peak around the same time."

"We do not yet have a COVID-19 vaccine, but safe and moderately effective influenza vaccines are available. Their widespread use is more important now than ever, and we encourage health care providers, employers, and community leaders to promote vaccination," they add.

William Schaffner, MD, professor of preventive medicine and infectious diseases at Vanderbilt University, Nashville, Tennessee, agreed with his colleagues that seasonal flu vaccination is especially important this year.

He told Medscape Medical News that the Centers for Disease Control and Prevention (CDC) has informed the influenza vaccine workgroup of its Advisory Committee on Immunization Practices (ACIP), of which he is a member, that the agency is planning a major public awareness campaign this year to raise the percentage of people who get flu shots.

The CDC confirmed it is planning such a campaign.  

"This season, getting a flu vaccine is more important than ever as it will not only protect against flu, but it also will help preserve scarce medical resources for healthcare providers and COVID-19 patients," agency spokesperson Kristen Nordlund told Medscape Medical News.

"CDC is developing and will roll out new communications materials to increase awareness about the importance of flu vaccination this season, especially among people who are at higher risk for flu and COVID-19," she added.   

The CDC usually begins its annual flu vaccine campaign activities in a joint press conference with the National Foundation for Infectious Diseases. That news conference is scheduled for October 1, around the time flu vaccinations for the 2020-2021 season are expected to begin.

A successful campaign to raise vaccination rates would require the involvement of state and local public health departments, Gostin noted. These agencies need federal support in the form of a framework for an effective health communications strategy and funding to carry that strategy out, he said. The CDC didn't respond to Medscape Medical News' question about how it plans to support state and local health departments.

Effect of Flu Vaccination

Although not as lethal as COVID-19, seasonal influenza causes a lot of deaths, especially among the elderly. In 2018-2019, the United States had 35.5 million influenza cases, with nearly 500,000 hospitalizations and 34,200 deaths attributed to the virus, Gostin and Salmon noted in their JAMA article. The year before, a particularly nasty flu caused 79,400 US deaths.

The CDC recommends that every person 6 months and older get vaccinated for seasonal influenza. Despite adult vaccination coverage of only 45% in 2018-2019, Gostin and Salmon observed, the vaccine prevented approximately 4.4 million influenza cases, 58,000 hospitalizations, and 3500 deaths. Besides preventing flu infections, vaccines also reduce intensive care admissions and duration of hospitalizations.

The editorialists attribute the relatively low vaccination rate to "public perceptions of low effectiveness, along with safety concerns. While effectiveness is low compared with other vaccines, influenza immunization is very safe and cannot cause influenza."

National Effort

Gostin and Salmon are calling for a national effort to attain high influenza vaccine coverage, including near-universal coverage among healthcare personnel and other groups at high risk for COVID-19. This effort should include a mass communication campaign, tailoring messages to specific populations, they say.

Gostin and Salmon also note that adequate flu vaccine supplies must be produced to meet the demand if immunization coverage is increased. Vaccine shortages have occurred in the past, and some drug companies have stopped manufacturing vaccines because of low profits and high financial risks.

They propose in their JAMA commentary that the federal government absorb this risk through "advance purchase commitments" for flu vaccines.

Schaffner said he is confident there will be enough flu vaccine supplies to meet the demand this year, even if a government campaign persuades more people to get inoculated. Additional manufacturers have recently entered the flu vaccine field, he said, and these companies have assured the ACIP's influenza vaccine workgroup that they are prepared for a surge.

"If there's an increasing demand for the vaccine, the manufacturers have told us that they can gin up their production capacity," he said.

Overcoming Vaccine Hesitancy

Vaccine uptake will be limited unless more patients make routine clinical visits, the JAMA article noted. Consequently, physician offices must use best practices to protect their patients from COVID-19 infection and encourage them to get vaccinated.

Pharmacies can also provide flu shots, as many do now, and many pharmacy chains are already preparing for a big push for flu vaccines this fall; schools and universities can also mount flu vaccination campaigns if they reopen. Businesses can take advantage of federal regulations that allow them to require influenza vaccination as a condition of employment.

Schaffner concurred. "Part of the message that has to go out is that you can be inoculated safely, and it's important to do this now. This is especially important because elderly people and vulnerable people with underlying conditions are those who are sheltering at home the most. They're being the most cautious about getting out there."

Gostin and Salmon emphasize that as many healthcare workers as possible should be immunized against the seasonal flu. In 2018-2019, they point out, the flu vaccination rate among healthcare personnel was 81%. This year, they say, "higher vaccine coverage should be a national priority."

State laws, they note, require workers at healthcare facilities to receive flu shots, but only if they consent. Many hospitals, however, have made influenza vaccination mandatory over the past decade, Schaffner said, adding that big institutions like Vanderbilt University Medical Center have vaccination rates in the 95% range.

Flu vaccine coverage is considerably lower in outpatient clinics, he added. Even if ambulatory care physicians do hospital rounds, they may not ensure their office staffs are inoculated, he noted.

Social Media Misinformation

In their Science op-ed, Belongia and Osterholm warn that social media is spreading misinformation about flu shots, such as the claim that they increase the risk of SARS-CoV-2 infection.

"Scientists, health care providers, and public health leaders must counter these claims with clear, evidence-based information on the importance of influenza vaccination during the COVID-19 pandemic," they say.

Belongia and Osterholm emphasize the importance of social distancing and other measures at vaccination sites to minimize the risk of SARS-CoV-2 infection, "particularly because many influenza vaccine recipients are at high risk for both influenza and COVID-19 complications."

It's unclear when COVID-19 patients should receive flu shots, they add, "but it may be prudent to delay vaccine administration until after the acute illness has been resolved."

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