While it can be difficult to predict some aspects of the flu season – such as which strain will be dominant or how intense this year’s flu season will be – the thing doctors know for certain is that the flu season will be here during the fall and winter months. An expert at Baylor College of Medicine’s Influenza Research Center gives advice on how to prepare.
“In an average year, we expect to see influenza activity in late November or early December, for it to peak in January or February and for it to finally leave sometime in April or even May,” said Dr. Pedro A. Piedra, professor of molecular virology and microbiology and pediatrics at Baylor.
Each year, there is the option to take the live attenuated vaccine, which is in the form of a nasal spray, or the inactivated vaccine, which is the flu shot. This year, the live vaccine will have two A strains and two B strains, making it a quadrivalent vaccine. For the flu shot, there will be the option to get a trivalent or quadrivalent vaccine.
According to Piedra, this year’s trivalent vaccine has been redesigned, with two out of three vaccine strains from previous vaccines replaced with new strains. The one that will remain the same is the pandemic H1N1, or the A/California strain. The H3N2 component will change to a strain called A/Switzerland, which was prevalent last flu season and was one of the H3N2 strains that caused the mismatch between what was circulating and what was in the vaccine for last year. The B strain will be replaced with the B/Phuket. The quadrivalent vaccine has two B strains from different lineages, the second B component being the B/Brisbane, which is not a new strain.
“When you go to your healthcare provider this year, you may have the opportunity to have a trivalent or quadrivalent vaccination. I would say in general, if the quadrivalent formulation is available, that probably would be the better option because it’s going to ensure that you have coverage against any of influenza B lineages that may circulate,” said Piedra. “If you only have the option of the trivalent vaccine, I would still strongly recommend getting the vaccine.”
Most of the vaccines are slowly transitioning into a quadrivalent vaccine, but both will be available this year.
Who should be vaccinated
In the United States, it’s recommended that everyone over the age of 6 months should be vaccinated.
“We truly believe that universal immunization is the best way to protect everybody against flu,” said Piedra. “Although you have risk groups who are more likely to get severe disease, you have other groups like school-aged children who are more likely to get infected and spread it to others in the community. An outbreak needs individuals who are susceptible to the infection; one way to minimize those who are susceptible to the infection is to protect them with a vaccine. The more people who are protected against what’s circulating, the less likely that an influenza season will be able to take hold or cause complications.”
He notes that vaccination provides direct benefit to those who are vaccinated and starts to provide indirect benefits to those who are not vaccinated but are vulnerable.
Who should get which vaccine
“We have many approved inactivated and live influenza vaccines that target different age groups,” said Piedra.
The live vaccine, or the nasal spray, is approved for healthy individuals between 2 and 49 years of age. The inactivated vaccine, or the flu shot, is approved for individuals 6 months of age and older.
There is now a high-dose influenza vaccine for adults 65 years and older because it produces a better immune response in this age group, which generally translates into better protection. Older adults don’t respond like healthy adults to the vaccine, so this high-dose vaccine contains four times the concentration as the regular influenza vaccine.
All family members that older adults surround themselves with should be vaccinated against flu because that is the best way for them to be protected.
It is recommended that pregnant women be vaccinated during any trimester. They must receive the inactivated vaccine, or the flu shot.
“When the mother is vaccinated she will transfer the antibodies through the placenta to her infant, who thereby will be passively protected during the first six months of life. This will reduce the risk of hospitalization in those first six months, which is substantially high,” said Piedra.
Anyone in the healthcare environment should be protected against flu to reduce the risk of spreading it to others who would be very susceptible in a high-risk setting like a hospital.
If you have a significant allergic illness to one of the vaccine components, such as eggs, you would not want to receive an egg-based influenza vaccine, but you could still receive a cell-based influenza vaccine.
Individuals with Guillain-Barre Syndrome should speak with their physicians to weigh the risk versus the benefit of getting the influenza vaccine.
Piedra said not to wait until the flu is here to get vaccinated because it reduces the time that the vaccine can provide protection during the flu season. The vaccine takes about one to two weeks to give full protection against the virus.
Infants and young children 8 years and younger who have never been previously vaccinated will need a second dose four weeks after the first dose.
Those experiencing flu-like symptoms should consult with their physician to get the appropriate medications to treat the infection.
“These anti-influenza drugs have to be started early in the illness for best benefit,” said Piedra.