{"id":17726,"date":"2018-09-19T14:20:30","date_gmt":"2018-09-19T19:20:30","guid":{"rendered":"http:\/\/thepapergown.zocdoc.com\/?p=17726"},"modified":"2023-03-03T15:09:50","modified_gmt":"2023-03-03T20:09:50","slug":"everything-you-need-to-know-about-the-flu-shot","status":"publish","type":"post","link":"https:\/\/www.zocdoc.com\/blog\/guides\/everything-you-need-to-know-about-the-flu-shot\/","title":{"rendered":"Your Guide to the Flu Shot"},"content":{"rendered":"

This story has been updated for the 2019\u20132020 flu season.<\/em><\/p>\n

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The flu is a reliably serious public health problem. Last year’s flu season lasted 21 weeks \u2014 the longest in a decade \u2014 and caused more than 500,000 hospitalizations and at least 36,000 deaths, according to the Centers for Disease Control and Prevention<\/a>. (Those numbers were even higher the previous year.)<\/span><\/p>\n

Even so, a lot of people drag their feet when it comes to getting a flu shot. In a given year, only about 40 percent of adults<\/a> get vaccinated. Dr. Pedro A. Piedra<\/a>, a physician and researcher at the Vaccine Research Center, would like to see that number, called flu coverage, rise to 80 percent.<\/p>\n

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People cite all sorts of reasons for opting out of vaccination. Some worry they\u2019ll get sick from the flu shot itself, while others distrust vaccines generally or believe the vaccine is pointless since it doesn\u2019t protect against every strain of the flu. Still others assume that a flu-free past means a flu-free future. But in the vast majority of cases, experts say there\u2019s no justification for riding out the flu season without protection.<\/span><\/p>\n

\u201cLast year we had an unusually long influenza season with two major overlapping outbreaks. The year before, we had an influenza season that caused very high attack rates, high hospitalizations and high mortality in both children and older adults,\u201d says Piedra, who is also a professor of virology and microbiology at Baylor College of Medicine in Houston. \u201cWhat will happen this year, we can\u2019t predict. But I can say that the flu will circulate and will cause problems, and the best way to protect yourself from it is to be vaccinated.\u201d<\/span><\/p>\n

The flu shot: backstory and basics<\/b><\/h2>\n

The influenza virus was first isolated in a laboratory in the early 1930s, and a vaccine has been in use since the end of World War II. The flu isn\u2019t a single virus: There are two main types of influenza, A and B, each with multiple strains. The diseases caused by all of these viral strains are collectively called \u201cthe flu,\u201d and between 9.2 million and 35.6 million people<\/span> get it every year<\/span><\/a>. The vaccine helps the body produce an antibody response that prevents viral infection.\u00a0<\/span><\/p>\n

Early flu-shot guidelines focused on vaccinating high-risk populations, meaning children, the elderly and people with compromised immune systems. Once<\/span> Medicare began covering flu shot costs for patients in 1993<\/span><\/a>, vaccination became more widespread in the U.S. In 2010, the CDC began recommending flu shots for everyone 6 months old and up.<\/span><\/p>\n

The disease primarily spreads from the mouth, nose and eyes when infected people talk, cough and sneeze. It’s also possible to pick up the flu if you touch a surface harboring the virus and then touch your face, although this mode of transmission is less common. Symptoms can include fever, body aches, fatigue and sometimes diarrhea and vomiting. Most people will only get mildly ill from the flu and won\u2019t need medical care or antiviral drugs, says Bert Kelly, a spokesman for the CDC. But one person\u2019s mild case of the flu can turn into another person\u2019s serious illness. That\u2019s why the CDC asks that anyone with the flu stay home, refrain from travel and avoid contact with other people except to get medical care.<\/span><\/p>\n

These instructions might seem obvious, but in<\/span> a 2018 consumer poll of more than 2,000 CVS customers<\/span><\/a>, two-thirds of respondents said they\u2019d go to work with the flu, either because they didn’t want to use paid time off or because they’d be expected to work through sickness. Respondents also said flu symptoms wouldn\u2019t prevent them from going to the grocery store (28 percent), picking up children at school (12 percent) or taking public transportation (10 percent).<\/span>
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Why flu vaccines change every year<\/b><\/h2>\n

Influenza viruses mutate constantly, which is why vaccines need to be updated. Each year, researchers figure out the strains by analyzing data collected from early cases of the flu in a worldwide surveillance network. Once the virus is isolated in patients, doctors conduct testing to determine the virus subtype.<\/span><\/p>\n

The next step entails even further testing to understand the composition of the major viruses circulating among flu-infected people. Once researchers have a best guess of which strains are most likely to spread, they develop vaccines anywhere from three to six months in advance of flu season. Each vaccine contains three or four different strains of the flu. <\/span>When the vaccines match the types of flu going around, flu risk among the general population drops by 40 to 60 percent, according <\/span>CDC research<\/span><\/a>. <\/span>But even if their best guess is wrong, and there isn’t a perfect match between the vaccines and the current flu strains, getting vaccinated still provides some protection against infection.\u00a0<\/span><\/p>\n

CDC research suggests that four strains are responsible for this year’s flu season: H1N1 (the strain behind the 2009 pandemic), H3N2, and two main lineages of the B virus. V<\/span>accines for both H1N1and\u00a0H3N2<\/a> have been updated since last year, while the B-virus vaccines are unchanged.<\/p>\n

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How the vaccine protects you (and everyone else)<\/b><\/h2>\n

It takes about two weeks for the flu vaccine to take effect. During that time, the body develops antibodies to fight the virus. Some people are more sensitive to the flu shot and might experience mild flu-like symptoms afterward, but<\/span> the flu shot will not give you the flu<\/span><\/a>. In addition, some people might experience soreness at the injection site, but it only lasts a day or two.<\/span><\/p>\n

The<\/span> CDC estimates<\/span><\/a> that flu vaccines are about 30 percent to 60 percent <\/span>effective<\/span><\/a> in any given year. That might sound low, but there\u2019s something else at play: herd immunity. Populations can collectively stop flu transmission if enough people are immune to infection.<\/span><\/p>\n

\u201cThe definition of \u2018enough,\u2019 that magic number, is based on how transmissible the infection is,\u201d says<\/span> Stephen S. Morse<\/span><\/a>, an epidemiologist at the Mailman School of Public Health at Columbia University. \u201cThere are some standard ways to model this mathematically.\u201d<\/span><\/p>\n

A 50-percent vaccination rate would be enough to stop flu transmission in a geographic area. By contrast, it would take a 95-percent vaccination rate to build herd immunity to measles, which is about 10 times as transmissible as the flu.<\/span><\/p>\n

\u201cEven if a vaccine is only partially effective,\u201d Morse says, \u201cit will still reduce transmission significantly, as well as protecting you.\u201d<\/span><\/p>\n

Plus, if you do contract a strain of the flu despite being vaccinated, your symptoms will likely be more mild than if you hadn\u2019t gotten one.<\/span>
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Does everyone get the same flu shot?<\/b><\/h2>\n

Most but not all<\/span><\/a> flu vaccines are administered via injection. The reasons to get a particular type primarily come down to age and health status. It\u2019s not your responsibility to choose the right flu vaccine; doctors, nurses, pharmacists and anyone else administering vaccines should collect enough information from you to make a selection on your behalf.<\/span><\/p>\n

Here are the commonly <\/span>available vaccines<\/span><\/a>:<\/span><\/p>\n