How effective is the flu shot? It's still too soon to tell, despite an exceptionally harsh flu season
The Centers for Disease Control (CDC) announced that it's too soon to tell how effective this year's flu vaccines will be against the different viruses in circulation. Right now, the CDC announced that more people are catching the flu than is usual this time of year, and that it expects this trend to continue for at least the next few weeks. The CDC announced that the most common flu viruses in circulation in the US so far are B/Victoria viruses and A(H1N1)pdm09 viruses. This year's flu vaccine is designed to protect against both of these types of viruses. However, how effective it is, remains to be seen. This article was reviewed by Tania Elliott, MD, who specializes in infectious diseases related to allergies and immunology for internal medicine at NYU Langone Health.
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It's still too soon to tell how effective this year's flu vaccine is, according to the Centers for Disease Control (CDC). But it's still a good idea to get the shot. The CDC reports that flu activity is unusually high in the US and will likely continue to be high for the next few weeks. So far, an estimated 9.7 million people have contracted some form of the flu virus and 32 have died. And Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, tells CNN that we're in for a bad flu season, overall, based on what the CDC has seen so far. The flu vaccine is the most effective way to protect yourself against infection from the influenza virus. The latest reports from the CDC indicate that the main virus infections people right now are B/Victoria viruses, which hasn't happened in nearly 30 years.
Influenza B viruses have not predominated nationally in the U.S. since 1992, and over the last 3 seasons have accounted for <10% of circulating flu viruses. However, between Sep. 29 and Dec. 28, influenza B accounted for 60% of viruses circulating in the U.S. (1/3) pic.twitter.com/Bcl7BBktlv — CDC Flu (@CDCFlu) January 13, 2020
This year's flu vaccine is designed to protect against both strains of H1N1 and B/Victoria viruses. However, how the unusually large number of influenza B viral infections will affect the vaccine's effectiveness remains to be seen. But no matter how effective the flu vaccine is, it's not 100% effective. In fact, it's not even close. How effective is the flu vaccine? How effective the flu vaccine is will vary from year to year. In a good year, when the flu vaccine is most effective, it can reduce your risk of getting sick by 60%. That means you have at least a 40% chance of getting the flu if you are exposed to it, even if you're vaccinated. But that's better than a bad year when the flu vaccine's effectiveness can dip below 20%, meaning you still have more than an 80% chance of getting the flu if you are exposed to it. So why the big difference? For most healthy adults, the chance of getting the flu after being vaccinated largely depends on the vaccine itself. Each year, flu vaccines are designed to protect against three to four different viral strains of influenza. Most often, the World Health Organization selects those strains for the upcoming flu season in the Northern Hemisphere from viruses that have been circulating in the Southern Hemisphere in the previous six months. But sometimes the viral strains that end up in the flu vaccine for the US and the rest of the Northern Hemisphere don't match the viral strains that end up circulating come flu season. This can happen when a new viral strain arises at the wrong time. "Every once in a while there's a surprise and something emerges late in the season that's unexpected, and that's one reason the vaccine is not 100% effective," says Graham Snyder, MD, medical director of infection prevention at the University of Pittsburgh Department of Medicine. In this case, when the strains in the vaccine don't match the strains making people sick, it can mean a less effective flu vaccine — well below 60% effectiveness — and a greater chance of still getting the flu after your shot. For instance, this is exactly what happened during the 2014-15 flu season. That year there were multiple strains of a type of flu virus, called H3N2, going around. But the vaccine didn't have a strain that matched most of the H3N2 strains that were making people sick. So researchers estimated that the flu vaccine was only 13% effective against H3N2 that season. This helps explain why the 2014-15 flu season had some of the highest percentages of hospitalizations and deaths from influenza compared to the five flu seasons before it. That said, during the more moderate 2016-17 flu season, when the flu vaccine was estimated to be 40% overall effective, flu vaccines prevented an estimated 5.3 million flu-related illnesses and 2.6 million medical visits, according to the CDC. For this year's vaccine, the FDA has recommended it contain a type of H1N1, H3N2, and two versions of flu-type B. So the effectiveness of this year's vaccine will depend on which flu virus circulates this flu season. For more information about this year's flu vaccine, visit the CDC's website. What are other flu vaccine options?
The nasal-spray vaccine can be an ideal alternative for people afraid of getting the flu shot, including children over the age of 2, but how effective it is can vary year to year. For example, a 2019 study published in the Official Journal of the American Academy of Pediatrics found that the nasal spray vaccine for the 2018-19 flu season was less effective than the flu shot in protecting children from getting two common strains of the flu, H1N1 and H3N2. But the nasal spray has since been reformulated for upcoming seasons. The nasal vaccine is a live, weakened version of the virus, and is not recommended in anyone who has a weakened immune system, pregnancy, or chronic medical problems. There is also a high-dose flu shot that contains more virus particles than the regular shot so that the immune system is stimulated more rigorously. This inoculation is for people aged 65 and older whose immune system may not be as strong. When this population receives a regular-dose flu shot, they may not produce as many protective antibodies and therefore are at a higher risk of getting sick with the flu. A 2014 study published in the New England Journal of Medicine showed that people 65 and older who received the high-dose shot suffered 24% overall fewer illnesses from influenza compared to older adults who received the standard dose. "I encourage people to talk to their doctor about what type of vaccine is best for them," Snyder says.
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Drugs that prevent and treat the coronavirus are critical to stemming the pandemic. Here are the most promising treatments that could be ready by the fall.
Drugmakers are racing to find effective treatments and vaccines to mitigate the effects of the coronavirus...Drugmakers are racing to find effective treatments and vaccines to mitigate the effects of the coronavirus pandemic. While early vaccine research has been promising, in the absence of a highly effective vaccine, additional medications are needed to prevent and treat the virus. Among those in the works are antivirals, as well as treatments that harness the body's immune system to go after the virus. Repurposed drugs like remdesivir have already been cleared for emergency use, while others like Regeneron's antibody treatment are looking to be available by the fall. For more stories like this, sign up here for our healthcare newsletter, Dispensed. Drugmakers are racing to mitigate the impact of the coronavirus pandemic. As part of that, researchers are developing vaccines to prevent infections and repurposing existing medications to treat people with COVID-19, the disease caused by the novel coronavirus. Drug developers are also working on treatments to help fight the virus itself. While early vaccine results have been promising, in the absence of a highly effective vaccine, treatments that help people who get infected with the novel coronavirus will be key. For instance, influenza vaccine effectiveness can range from year to year, from relatively low effectiveness like 19% effective for the 2014-15 season to as much as 60% effectiveness in the 2010-11 season. When combating the flu, treatments like Tamiflu can be used to lessen symptoms and sometime act as a preventive measure. One repurposed medication aimed at treating coronavirus infections has already been approved for emergency use. Others, too, have proven useful in combating some of the severe symptoms brought on by COVID-19 that have led to tens of thousands of hospitalizations. A slate of newly created medications are also currently being tested, and some could be approved as soon as this fall. Read more: Drugmakers are racing to use existing medicines to fight the coronavirus. Here's what you need to know about the 14 most promising medications being put to the test. Drugmakers are repurposing antiviral drugs to treat COVID-19, and one has already been given emergency authorization Antivirals work by targeting the virus to keep it from replicating in the body, bringing on more symptoms. Antivirals are used to treat the flu, as well HIV. So far, one has been given emergency authorization: Gilead Sciences' remdesivir. Study results have shown that the drug helped hospitalized patients with COVID-19 recover faster than those receiving a placebo. The Food and Drug Administration on May 1 issued an emergency authorization for the drug's use. Remdesivir isn't the only repurposed antiviral being tested to treat COVID-19. Another is Avigan, an influenza treatment and broad-spectrum antiviral drug made by Fujifilm Toyama Chemical. It's not approved in the US. The drug has been approved for use in COVID-19 in Russia and India, but plans for its approval in Japan by May fell short because there wasn't enough evidence of how well it worked in treating the disease. Read more: Gilead built a biotech colossus by treating viruses like HIV and hepatitis C. Now, it stands to make billions from the first effective coronavirus treatment. Drugmakers are looking to have newly created drugs that prompt the body to fight the virus available by the fall Researchers are also exploring an approach that uses the body's immune reaction to viruses to lessen symptoms and potentially prevent people from getting sick in the first place. The approach uses the body's own disease-fighting proteins, called antibodies, as the basis for drugs. The hope with these treatments is to infuse the body with antibodies to fight the novel coronavirus, helping the body mount a better immune response. Trials are ongoing from drugmakers Regeneron, Eli Lilly, and Celltrion to see if the treatments work both to stave off infection as well as to treat COVID-19 patients with moderate or severe illness. Regeneron and Lilly are expecting results that make it clear whether or not the drugs work as soon as the fall. Read more: An antibody treatment might be our best shot at stopping the coronavirus if a vaccine doesn't work out. Here are the 9 leading programs, including 2 that are aiming to be ready this fall. Treatments based on plasma offer another solution One approach to treating coronavirus infections that's already in use is convalescent plasma. That uses the blood of those who have recovered from the illness — specifically the antibodies they produced — to fight the virus. It's a treatment has been around for decades. Trials testing the benefit of convalescent plasma in COVID-19 are ongoing, with some early results suggesting some benefit. Using convalescent plasma is constrained by blood donations. Drugmakers are also looking to make treatments based on more purified forms of plasma that can be used more widely. The product, known as hyperimmune globulin, is made when scientists purify the plasma to focus on a specific type of antibody called IgG. Takeda, Japan's largest pharmaceutical company, is working with a coalition of 10 drugmakers to develop the treatment. An international trial of hyperimmune globulin is expected to start in July and wrap up in the fall, with the hopes of getting approval by the end of 2020. Read more: Doctors are using the blood of coronavirus survivors to treat patients with the disease. 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