Know what flu protection is right for you

When I went to a pharmacy in Brooklyn to get a flu shot last year, I was presented with a choice: one vaccine with three different strains of the flu virus for about $30 or, for just $10 more, four strains. It sounded vaguely like a late-night television infomercial.

I stood at the counter, confused. Didn't I want every strain? I thought that one new vaccine was developed each year and that it was more effective some years than others. What was I missing?

As it turns out, the choice I was given was not unusual. Until a few years ago, the typical flu shot included three strains of the virus in what is known as a trivalent vaccine: two strains of influenza A, one of influenza B. Now, more flu-shot makers are adding a second B strain to create a quadrivalent vaccine that provides a bit more protection.

The more strains the better, right? I paid for the additional B strain. The vaccine experts I spoke with later said that was a good choice for me, but that didn't mean it would be better for everyone based on what's available now. The Centers for Disease Control and Prevention said it did not prefer one vaccine over another. Its guidelines are based largely on age and other characteristics (like pregnancy or chronic illness).

This year there are at about six types of vaccine. Whether your employer or insurer pays for it, or you do, it's worth studying the options to determine which is likely to protect you the most.

How serious is the flu?

There were more than 80,000 flu-related deaths in the United States last winter. People older than 65 accounted for nine out of 10, but the flu also killed 180 young children and teenagers, according to the CDC.

Despite the risks, according to CDC estimates, only 37.1 percent of adults 18 or older were vaccinated last flu season, down 6.2 percentage points from the year before, and 58 percent of children 6 months to 17 got at least one shot.

What types of vaccine should I get?

The type of shot you should get is generally based on your age.

High-dose shot

Older people often have weaker immune responses to the vaccine, so experts suggest those 65 and older get either a high-dose shot, which has four times the regular dosage, or a shot with adjuvant, an ingredient that boosts immune response.

These special formulations are 3 to 10 percent more effective for those 65 and older, said Dr. Paul Offit, a professor of pediatric infectious diseases at Children's Hospital of Philadelphia. Both are currently offered only in trivalent formulations.

Anyone else 6 months to 64 may be better off getting a quadrivalent shot, experts said. Quadrivalent vaccines are in wide use - between 114 million and 124 million of the 163 million to 168 million doses projected to be available for the current flu season, according to the CDC - but don't hold out for one.

“It is more beneficial to get covered with the trivalent vaccine, rather than wait or search for the quad,” said Dr. Frank Illuzzi, chief medical officer at CityMD, an urgent care chain.

For younger people, including children afraid of needles, the nasal spray vaccine, which has live - but attenuated, or weakened - viruses, may be a good option, said Dr. Gregory Poland, director of the Mayo Vaccine Research Group.

The spray, available in a quadrivalent formulation this season, is approved for people 2 to 49 who are not pregnant.

The CDC did not recommend the spray during the past two seasons because it was ineffective the two years before that. But the formulation was changed, and it is back on the list of recommended options for those in the appropriate age range (if they don't have certain medical conditions).

The American Academy of Pediatrics said it recommended the shot as its first choice, however, for children.

Do I have to worry about the effects of any ingredients?

In the past, people with egg allergies had to take special precautions when getting flu shots because many of the viruses used in vaccines are grown in eggs.

As of the 2016-17 flu season, those with a history of “egg allergies of any severity” may receive any licensed flu vaccine appropriate for their age group, the CDC says. Those with a history of severe allergic reactions - more than just hives - should get the vaccine in a medical setting.

Some people worry about whether flu shots contain thimerosal, an additive containing ethylmercury that is no longer used in any children's vaccines. Thimerosal is still used to help prevent the growth of germs in vaccine vials that contain multiple doses. Vaccine experts, and the CDC, say this use is safe. But because many flu shots are single dose, thimerosal is often not an issue for adults, either.

How effective are flu shots?

Effectiveness varies each year. Because it takes at least six months to make and distribute the shots that become available in September, scientists have to make their best guess about which strains will circulate, and thus what to include in a vaccine, well in advance.

During that time - and even while vaccines are being produced - the circulating viruses can mutate, lessening the effectiveness of the chosen vaccine. It's an imperfect science.

“We do the best we can,” said Offit, who also sits on the Food and Drug Administration advisory committee that recommends which strains to include. “But you are trying to predict what is going to happen six months from now.”

Sometimes, he said, the experts guess wrong. In the 2014-15 season, the vaccine was only 19 percent effective. Last flu season, the overall vaccine effectiveness against both influenza A and B viruses was estimated to be 40 percent. In other words, it reduced your risk of having to seek medical care for the flu by 40 percent, according to the CDC.

Will I have to pay?

Most people with health insurance that complies with the Affordable Care Act are entitled to a flu shot without a co-payment or coinsurance.

Be sure to check with your insurer; it may require you to get a shot from your doctor or specific providers.

Medicare beneficiaries' flu shots are covered under Part B; beneficiaries pay nothing as long as the doctor or other provider accepts Medicare.

Medicaid covers flu shots for children and young adults through age 20. Adults eligible for Medicaid are also generally covered, though that can vary by state.

If you're not covered, prices vary depending on the type of vaccine. Walgreens said that more than 90 percent of the customers it vaccinates are covered by insurance. Those who are not can expect to pay $40.99 for a quadrivalent shot, while both options for those 65 and older - the high-dose shot and the one with adjuvant - each cost $69.99.

At CVS, the quadrivalent is $41.99, and the high-dose shot is $66.99.

Rite Aid offers a standard trivalent flu vaccine for $34.99 and a quadrivalent shot for $39.99. For people over 65, it offers Fluad, which includes adjuvant, for $74.99.

Walmart generally charges $39.88 for a quadrivalent shot; the high-dose is $69.78. Prices may vary by location.