Find out here, when we know! How effective is this year's flu shot?

Find out here, when we know! How effective is this year's flu shot?
Up to 11% of Americans are estimated to contract the influenza virus each year, and some patients develop more severe symptoms and require hospitalization. Fortunately, vaccinations help prevent diseases. Because there are many strains of influenza virus, vaccine formulations are regularly revised to continue to provide optimal protection.

"Influenza vaccine formulations are reviewed annually by the Centers for Disease Control and Prevention (CDC)," said Dr. Bernadette Boden-Albala, director and founding dean of the Public Health Program at the University of California, Irvine. .

Looking at this year’s flu vaccine
Given the potential for viral mismatch, how long will it take before we know if this year's vaccine is effective against the more common types of influenza? It may take a few more months to get a better understanding.

In recent years, influenza vaccination has provided approximately 43% protection against disease. This varies from year to year, but ranges from 60% for the 2010-2011 flu season to 19% for the 2014-2015 flu season. Influenza cases have increased this year, but the peak has not yet come. And only as more people get sick will experts be able to identify the most common strains and see how they compare to those used for injections.

The number of flu patients has increased this year, but the peak has not yet come. And only as more people get sick will experts be able to identify the most common strains and see how they compare to those used for injections. For example, by mid-December of the 2021 flu season, researchers found that the vaccine strain and the circulating flu virus were not a perfect match. However, flu vaccines are designed to work against multiple strains, so they say they still offer some protection. data is collected on an ongoing basis. "Predictions for the 2022-23 flu season will continue to be updated throughout the year," Boden-Albala said.

Flu vaccinations may also help relieve symptoms in people who do get sick, experts say.

Learning from other countries
Some think that looking at countries in the Southern Hemisphere with early flu seasons might provide clues as to what the virus might look like when it arrives in the Northern Hemisphere. In Chile, where the influenza season has begun, we have found that the predominant strain is one of the influenza A(H3N2) viruses. The virus also started to spread earlier this year, resulting in more hospitalizations than the 2020-21 flu season. "But the reliability of this approach is debatable," DrPH Matt Weissenbach, senior director of clinical operations at Wolters Kluwer Health, told his Healthline.

This is mainly because "confounding variables and limitations such as missing data and external factors that could not be controlled" were not considered. Still, Weissenbach continues, "It's still a worthwhile exercise when it comes to looking at forecasts for frequency, timing, and length across seasons." Started early. A similar pattern in the United States.

"Early in the season, some areas are already seeing flu outbreaks," he said. "It is entirely possible that there will be a steady increase in activity early in the season, as has been noted in many countries in the Southern Hemisphere."

What to know about the flu shot
By the end of October, more than 128.4 million people in the United States had been vaccinated against the 2022 flu. Vaccines target multiple types of influenza viruses. "All flu vaccines in the United States are 'quadrivalent' vaccines, meaning they protect against four different influenza viruses. :

  • Influenza A(H1N1) Virus
  • Influenza A(H3N2) Virus
  • Two Influenza B Viruses, Boden-Albara
, Boden-Albara explained. However, these antibodies do not last forever. This is another reason why it is wise to get the flu vaccine every year.

Numerous studies have looked at how effective flu vaccines are at protecting against the virus.The CDC estimated that vaccination could kill about 7.5 million flu infections and deaths during the 2019-2020 flu season. It is estimated that 105,000 flu-related hospitalizations were prevented.

Meanwhile, earlier this year in Chile, vaccination was associated with a 49% reduction in his A(H3N2) influenza virus hospitalization risk.

How the pandemic has impacted immunity

Boden-Albala shared that epidemiologists are predicting that the next flu season could be "bad." This is because one of the major strains expected to circulate is associated with more severe symptoms. But another reason more people may be affected? The aftermath of pandemic-related measures like wearing masks, social distancing, and staying home.

"Community containment measures implemented during the pandemic are thought to have had some impact on transmission of the influenza virus," said Weissenbach.

In addition, Boden-Albala explained that these measures "limited exposure to influenza in recent years." Therefore, "it would be expected that the flu could be exacerbated due to the low levels of antibodies in the circulation". However, it is not recommended for some rare individuals (such as those with certain allergies).

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