- #1
Drakkith
Staff Emeritus
Science Advisor
2022 Award
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- TL;DR Summary
- Reasons for the supposedly low effectiveness of the flu vaccine.
Good morning everyone. I woke up today and opened up Facebook only to see someone posting a meme about how in 70 years we've only developed a flu vaccine that's 40% effective, yet in 10 months we've developed a COVID-19 vaccine that's 95% effective. The implied meaning here is that the COVID-19 vaccine is a fraud and you shouldn't get it. I spent a few minutes posting a response in the comments and decided that I would make another post here at PF. My response:
1. Influenza (the flu) is caused by a family of related viruses, not a single virus. These are commonly called strains or subtypes, such as H1N1 or H3N2. A vaccine for H1N1 will not be very effective for H3N2 or other types.
2. The influenza viruses have the ability to exchange genetic information when two different types infect one host, which greatly accelerates their genetic mutation rates and also enables them to create new, novel subtypes that have never existed before.
3. Because of the multiple strains and the ability to quickly create novel subtypes, vaccine producers have to make educated guesses as to which subtype will be most prevalent for the coming flue season and target their vaccine accordingly. If they are wrong, then the vaccine will be much less effective.
4. Flu vaccine effectiveness is problematic to measure, as it is measured by using the rates of influenza-like illnesses, which are caused by many different diseases. This is a major reason why the efficacy (effectiveness in a controlled setting) is much higher than the real world effectiveness. It's not that the vaccine is ineffective, it's that a high proportion of people who think they have the flu actually don't.
Do not let fear and suspicion rule your health decisions. Educate yourselves, everyone.
-Drakkith
1. Influenza (the flu) is caused by a family of related viruses, not a single virus. These are commonly called strains or subtypes, such as H1N1 or H3N2. A vaccine for H1N1 will not be very effective for H3N2 or other types.
2. The influenza viruses have the ability to exchange genetic information when two different types infect one host, which greatly accelerates their genetic mutation rates and also enables them to create new, novel subtypes that have never existed before.
3. Because of the multiple strains and the ability to quickly create novel subtypes, vaccine producers have to make educated guesses as to which subtype will be most prevalent for the coming flue season and target their vaccine accordingly. If they are wrong, then the vaccine will be much less effective.
4. Flu vaccine effectiveness is problematic to measure, as it is measured by using the rates of influenza-like illnesses, which are caused by many different diseases. This is a major reason why the efficacy (effectiveness in a controlled setting) is much higher than the real world effectiveness. It's not that the vaccine is ineffective, it's that a high proportion of people who think they have the flu actually don't.
Do not let fear and suspicion rule your health decisions. Educate yourselves, everyone.
-Drakkith