Vaccine Discussion Master Thread

[CountValentine]

I guess we differ on equating getting the flu to being in a bad accident.

We probably look at the probabilities differently also without even considering risk vs reward.

[imayid2]

Why does the CDC say it has a 40-60% efficacy rate if it has an average of less than 40% for the past 10 years?

[CountValentine]

Why does the CDC say it has a 40-60% efficacy rate if it has an average of less than 40% for the past 10 years?

Past results are not predictive of future results.

[imayid2]

Past results are not predictive of future results.

Ok so let them say 19-60. Why 40-60?

[CountValentine]

Ok so let them say 19-60. Why 40-60?

It is based on predictions. IIRC this shot will cover 4 variants.

[imayid2]

The dominant strain this season is H3N2 for which the vaccine has a much lower efficacy rate.

[CountValentine]

The dominant strain this season is H3N2 for which the vaccine has a much lower efficacy rate.

The season didn't really even start yet, has it?

"Both the influenza A(H3N2) and the influenza B(Victoria lineage) vaccine virus components were updated."

[Dan]

H3N2 for which the vaccine has a much lower efficacy rate.

Link?

[Dan]

https://www.fda.gov/vaccines-blood-biologics/lot-release/influenza-vaccine-2022-2023-season

The committee recommended that the quadrivalent formulation of egg-based influenza vaccines for the U.S. 2022-2023 influenza season contain the following:

an A/Victoria/2570/2019 (H1N1)pdm09-like virus;
an A/Darwin/9/2021 (H3N2)-like virus;
a B/Austria/1359417/2021-like virus (B/Victoria lineage); and
a B/Phuket/3073/2013-like virus (B/Yamagata lineage).

[imayid2]

https://www.fda.gov/vaccines-blood-biologics/lot-release/influenza-vaccine-2022-2023-season

The committee recommended that the quadrivalent formulation of egg-based influenza vaccines for the U.S. 2022-2023 influenza season contain the following:

an A/Victoria/2570/2019 (H1N1)pdm09-like virus;
an A/Darwin/9/2021 (H3N2)-like virus;
a B/Austria/1359417/2021-like virus (B/Victoria lineage); and
a B/Phuket/3073/2013-like virus (B/Yamagata lineage).

They try to target it but it’s less efficient

[imayid2]

Link?

On the CDC website where they explain vaccine efficacy. Don’t have the exact url this second

[Dan]

H3N2 for which the vaccine has a much lower efficacy rate.

On the CDC website where they explain vaccine efficacy. Don’t have the exact url this second

Strong words to post without good sourcing. It's already impressive that they predicted H3N2 and included it in the vaccine for this season.

[imayid2]

Strong words to post without good sourcing. It's already impressive that they predicted H3N2 and included it in the vaccine for this season.

https://www.cdc.gov/flu/vaccines-work/vaccineeffect.htm#why_flu_vax_less_effective_against_H3N2
Why is flu vaccine typically less effective against influenza A(H3N2) viruses?
There are a number of reasons why flu vaccine effectiveness against influenza A(H3N2) viruses may be lower.

While all flu viruses undergo frequent genetic changes, the changes that have occurred in influenza A(H3N2) viruses have more frequently resulted in differences between the virus components of the flu vaccine and circulating influenza viruses (i.e., antigenic change) compared with influenza A(H1N1) and influenza B viruses. That means that between the time when flu viruses are selected to begin producing vaccines and when flu vaccines are delivered, A(H3N2) viruses are more likely than A(H1N1) or influenza B viruses to have changed in ways that could impact how well the flu vaccines work.
Growth in eggs is part of the production process for most seasonal flu vaccines. While all influenza viruses undergo changes when they are grown in eggs, changes in influenza A(H3N2) viruses tend to be more likely to result in antigenic changes compared with changes in other influenza viruses. These so-called “egg-adapted changes” are present in vaccine viruses recommended for use in vaccine production and may reduce their potential effectiveness against circulating influenza viruses. Other vaccine production technologies, e.g., cell-based vaccine production or recombinant flu vaccines, do not use eggs in vaccine production to avoid egg-adapted changes to the viruses used to make vaccines. CDC also is using advanced molecular techniques to improve flu vaccines.
Top of Page
How effective are flu vaccines in older adults?
In numerous studies since 2010, flu vaccines have helped protect older adults against influenza. Flu vaccination has reduced the risk of medically attended illness caused by A(H1N1) or influenza B viruses by more than 60% among people 65 years and older (1). Flu vaccines also have reduced the risk of flu hospitalization among adults 65 years and older due to A(H1N1) and influenza B(2). However, protection against influenza A(H3N2) viruses has been less consistent. On average, flu vaccines have reduced the risk of doctor visits for people with A(H3N2) flu by 24% and reduced the risk of hospitalization with A(H3N2) flu by 33% in adults 65 years and older (1,2). During seasons when the H3N2 vaccine component has been well-matched to the flu viruses circulating in the community, the benefit from flu vaccination has been higher. During these seasons, flu vaccine reduced the risk of hospitalization with A(H3N2) flu by 43% on average (2). But when the vaccine component was less similar to viruses in the community, the protection has dropped to 14% (2).For older adults, some studies have shown that some newer vaccines (the high-dose inactivated vaccine, the adjuvanted inactivated vaccine, and the recombinant influenza vaccine) might be more effective than standard-dose inactivated vaccines without an adjuvant. Because flu viruses and effectiveness of flu vaccines can vary from one season to another, it isn’t known whether any one of these vaccines will always be more effective in every flu season.

[imayid2]

It's already impressive that they predicted H3N2 and included it in the vaccine for this season.

I believe it is included in the vaccine every flu season.

[imayid2]

Source?

https://publications.aap.org/pediatrics/article/143/2/e20182094/37316/Live-Attenuated-and-Inactivated-Influenza-Vaccine?autologincheck=redirected?nfToken=00000000-0000-0000-0000-000000000000

[Dan]

https://publications.aap.org/pediatrics/article/143/2/e20182094/37316/Live-Attenuated-and-Inactivated-Influenza-Vaccine?autologincheck=redirected?nfToken=00000000-0000-0000-0000-000000000000

@biobook Summary?

[jj1000]

@biobook Summary?

CONCLUSIONS:
From this pooled individual patient–level data analysis, we found reduced effectiveness of LAIV4 (The Nasal Spray Flu Vaccine) against influenza A/H1N1pdm09 compared with IIV, which is consistent with published results from the individual studies included.

[biobook]

@biobook Summary?

Limited computer access.  Will try later.

[biobook]

@biobook Summary?

Five earlier studies had found that the nasal spray vaccine and the injected inactivated flu vaccine were equally effective against two types of flu virus (B and A H3N2), but the nasal spray vaccine was less effective against H1N1. Those earlier studies were based on small groups (1000-6000 children each) which didn't reach statistical significance, so these researchers reanalyzed the data as a combined group of 17000 and reached the same conclusion, this time statistically significant.

It had been suggested that the relatively low effectiveness of flu vaccines might somehow result from repeated annual vaccinations, but analysis of this data found no support for that.  Those who came down with flu were no more likely to have been vaccinated the previous year than those who didn't.

Vaccine manufacturers try to improve the vaccine every year, so after seeing these results from the 2009-2015 years, they based the 2017-2018 vaccine on different variants, and the spray vaccine was more effective in 2017-2018 (according to preliminary analyses cited in this 2019 publication).

Some might think that 40% vaccine effectiveness is too low to make it worthwhile, but it's not negligible. If the chances of winning the lottery were 40%, everyone would participate.

[imayid2]

Some might think that 40% vaccine effectiveness is too low to make it worthwhile, but it's not negligible. If the chances of winning the lottery were 40%, everyone would participate.

Is it 40% effective against H3N2?