February is typically the cruelest month for the flu with thousands of infections, hundreds hospitalized and some dying in Maryland.
Not this year.
Due in part to the coronavirus pandemic and preventative measures associated with it, the influenza virus is downright rare in Maryland and across the nation. But researchers are wondering if there’s a chance that the flu shot you got in the fall may yet fend off a nasty infection — of COVID-19.
The flu season is not over and cases still could rise, but for now it appears at bay. Health experts believe the state has been spared a flu outbreak because of efforts to control the coronavirus. The flu virus never got a foothold in the fall and masks, distancing and extra hand-washing prevented it from mass spread.
“Whether the level vaccinated for the flu is low or high, I don’t think it’s having any real impact on flu cases we’re seeing in the state or the country,” said Eili Klein, an epidemiologist and an associate professor in the Johns Hopkins School of Medicine. ”People just aren’t having the normal level of contact.”
There have been remarkably few cases in Maryland this year, with just a few thousand people being tested for flu and just a few dozen positive results, according to the state’s voluntary reporting system. There were about 25,000 confirmed cases last year in February alone, traditionally the worst flu month.
There have been no more than a few people hospitalized at any point this season, compared with hundreds normally reported on any given day in February. There have been just three flu deaths, all reported in the fall.
Meanwhile, scientists have been looking at the annual influenza vaccine, and a range of others, to see if they help boost the body’s natural defenses enough to stop a case of COVID-19 or make cases less severe.
Studies of various vaccines don’t yet offer evidence. They only show that people vaccinated for other diseases also fared better against COVID-19. The reasons remain unclear, so researchers won’t yet promote vaccines for unintended purposes. But with COVID-19 vaccines still scarce and other disease outbreaks happening around the globe routinely, they said there were “hints” worth exploring.
“These have potential for the future,” said Dr. Robert C. Gallo, co-founder and director of the University of Maryland School of Medicine’s Institute of Human Virology. “We’ll question now and be ready.”
Gallo is working with a group of vaccine experts from the Global Virus Network, where he is an international scientific adviser, to explore use of the polio vaccine to boost what’s called innate immunity. That’s the body’s general defense mechanisms against foreign invaders, as opposed to the adaptive immunity that develops from vaccination against a specific disease.
Other researchers have looked at vaccines, including those for shingles, pneumonia, tuberculosis and measles-mumps-rubella, to boost innate immunity. (The 84-year-old Gallo said he used the MMR vaccine himself for some possible protection before he was scheduled for the COVID-19 vaccine.)
Scientists say innate immunity hasn’t been studied much and it will take time to uncover which vaccine, if any, is best to boost protections and for how long. The duration of any boost would likely be only months, rather than annually for the flu vaccine for protection from flu.
So far, the leading contenders appear to be vaccines made from live, weakened viruses rather than dead viruses. That’s the nasal spray versus the flu shot, for example. But a variety of vaccines are being considered.
One analysis published last fall by researchers from Johns Hopkins University and elsewhere found that countries that routinely deploy the Bacille Calmette Guérin, or BCG, vaccine against tuberculosis found deaths from COVID-19 were 5.8 times lower than countries that did not use the vaccine. Other clinical trials of that vaccine are underway.
A study published recently by University of Missouri School of Medicine researchers found children and young adults who got the flu shot had less severe cases of COVID-19.
“The flu vaccine was the single independent factor when we adjusted for age, race, co-morbitities and [body mass index],” said Dr. Anjali Patwardhan, a Missouri professor of pediatric rheumatology and child health. ”It was the single factor associated with better outcomes.”
She said the flu vaccine seems to promote “virus interference” in the patients, all under 21. And the phenomenon could help explain why some minority groups are faring worse during the COVID-19 pandemic. People who are Black and Hispanic tend to be vaccinated less.
Until there is proof, however, she said trying to promote a message about flu vaccine for COVID-19 could muddy messages to hesitant populations about the importance of accepting the two vaccines expressly authorized for use against COVID-19.
“But I don’t see any downside in encouraging people to get a flu vaccine for the flu,” she said. “We’re still in flu season and doctors’ offices and pharmacies have them.”
Nationally, about 53% of people have been vaccinated against the flu, up over last season, according to data from the U.S. Centers for Disease Control and Prevention. Public health officials had pleaded with the public to get vaccinated in order to prevent a dual pandemic of flu and COVID-19 that did not materialize.
The officials feared a repeat of last season when there were an estimated 38 million flu cases, 400,000 related hospitalizations and 22,000 associated deaths nationwide. In response, manufacturers produced more flu vaccine than ever, about 193 million doses.
The flu vaccination rate is about 56.5% among children generally, but over 58% for white children, less than 44% for Black children and about 53% for Hispanic children.
In Maryland, overall vaccination rates lag the nation with fewer than 30% vaccinated. Minorities received a disproportionately low share of the doses.
State officials did not offer an explanation the low vaccination rates.
Despite Maryland’s low vaccination rate, Klein, the Hopkins public health researcher, suggested that a big reason flu cases remain so low is there are so few kids are in school. They are very efficient spreaders of the virus, unlike with COVID-19, he said.
As children return to school in greater numbers, there is a chance that flu cases rise, though Klein believes COVID-19 preventative measures will continue to control cases.
But if they haven’t had a flu vaccination yet, he said, it would be a good time.
Lois Privor-Dumm, director of adult vaccines for Hopkins’ International Vaccine Access Center, said she worries that specifically targeting minority populations for flu vaccines now could be problematic.
Polling already shows higher levels of hesitancy among minority groups to take a COVID-19 vaccine.
“The concern is how that would be perceived when the threat is relatively low,” she said. “The risk in the minority communities could be one of, ‘Why now?’ ‘What is your motivation?’ and ‘Are you being paid by the pharma companies to do this?’”
Privor-Dumm said it could be helpful to promote flu vaccination as part of a broader message of good health practices. Minorities often have higher rates of chronic conditions that could be worsened by the flu and make them more susceptible to severe effects from COVID-19.
Dr. Richard Kennedy, co-director of the Vaccine Research Group at the Mayo Clinic in Minnesota, said he hopes strong evidence emerges that the flu vaccine and others help stave off COVID-19 and maybe other dangerous viruses.
That would give public health officials another tool when there isn’t a specific vaccine available.
He helped write a paper released last summer that looked at several vaccines’ impact on COVID-19. It analyzed data from 140,000 people and found those who got a vaccine for flu, polio, chickenpox, pneumonia, flu or measles-mumps-rubella in the past five years were less likely to get COVID-19 than those who weren’t vaccinated.
Kennedy said it’s possible when two viruses are genetically close, a vaccine can work against both, such as cowpox and smallpox. Another explanation could be protections come from virus memory cells. They are created after someone is vaccinated and survive for years, repeatedly generating a robust immune response when someone is reinfected with the same virus but also those similar enough.
He called that an “intriguing” possibility, though he feared pushing the idea could lead to lax behavior from a public increasingly impatient with safety measures. People might feel they don’t need a mask or to distance from others because they are protected.
“There is a hint of something here to look into,” Kennedy said. “It’s not fully cooked, but we should keep looking at the recipe and how to improve the recipe.”
Meanwhile, he and other public health officials welcomed the respite from the flu as they battle COVID-19.
“If we see places relaxing bans and people deciding not to wear a mask, we’ll see an uptick in cases,” Kennedy said. “There could be a lot of COVID and maybe some flu and other respiratory viruses. We’re not out of flu woods yet.”