Share this page!

Dr. Jeff Gilchrist Profile picture
Twitter logo
16 Sep, 10 tweets, 3 min read
COVID-19: Pfizer vs Moderna dosing and combo Flu-COVID-RSV

Have you ever noticed that Pfizer's COVID-19 vaccine uses 30 ug doses and Moderna is100 ug doses and wondered why (  )? 🧵1/
In real-world effectiveness studies, the Moderna vaccine seems to outperform Pfizer with higher protection.  Since the two vaccines are using the same COVID-19 spike protein design, the two major differences between the vaccines are the dose amount and the time between doses.  2/
Some scientists believe the improved performance is because Moderna's dose is more than 3x higher than Pfizer.  Studies have shown increased neutralizing antibody level production with higher doses of mRNA vaccine given to rats ( science.org/doi/10.1126/sc… ).  3/
Moderna has also applied for approval to use a 50 ug booster dose (half the original strength). The Financial Times spoke with the Chief Scientific Officer at Pfizer to get some more details ( ft.com/content/3ee3ef… ).  4/
Pfizer chose 30 ug because it was the minimum dose level that gave an immune response in older adults that was greater than the immune response from natural infection. Opting for a higher dose level might have run the risk of a greater incidence of side effects. 5/
In Canada the rate of adverse events is higher in Moderna with 34 reports per 100K doses administered compared to Pfizer with 22 per 100K ( health-infobase.canada.ca/covid-19/vacci… ).  Both are much lower than AstraZeneca with 71 per 100K doses.  6/
Moderna has also released some preclinical data about their new combination vaccine which combines 4 strains of flu virus, COVID-19, and 1 RSV virus (  ).  7/
It seems that immune response is very similar whether the vaccine includes mRNA for just 1 virus or all 6 at the same time (see image). 8/ Image
If you are interested in the other things that Moderna is working on you can find details from their investor day ( investors.modernatx.com/static-files/3… ).  9/
It looks like they are testing Beta and Delta variant specific vaccines and combinations, and a next-generation version that can be stored at 2-5 degrees Celsius among many other disease related research. 10/

• • •

Missing some Tweet in this thread? You can try to force a refresh
　

Keep Current with Dr. Jeff Gilchrist

Dr. Jeff Gilchrist Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!

PDF

Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @jeffgilchrist

Dr. Jeff Gilchrist Profile picture
18 Sep
COVID-19: MMR and Tdap vaccines may reduce severity of COVID-19

For some time now scientists hypothesized that immune memory for other viruses could potentially reduce severity of COVID-19 as well. 🧵1/
Analysis of a large and well-characterized COVID-19 patient cohort revealed that prior MMR (measles-mumps-rubella) and Tdap (tetanus-diphtheria-pertussis) vaccination associates with reduced disease severity and death ( cell.com/med/fulltext/S… ). 2/
How is that possible? A diverse immune T cell response controls viral infections and a major goal of vaccines is to induce a strong and durable T cell memory. Reactivation of memory T cells generated against a different pathogen could enhance immunity to novel pathogens. 3/
Read 11 tweets
Dr. Jeff Gilchrist Profile picture
17 Sep
COVID-19: UK vaccine updates: Boosters for 50+

JCVI is now recommending booster shots (3rd dose) be offered to those more at risk of serious disease for the following groups no earlier than 6 months after getting the second dose ( gov.uk/government/new… ). 🧵1/
- those living in residential care homes for older adults
- all adults aged 50 years or over
- frontline health and social care workers
- all those aged 16 to 49 years with underlying health conditions that put them at higher risk of severe COVID-19, and adult carers

2/
- adult household contacts of immunosuppressed individuals

3/
Read 16 tweets
Dr. Jeff Gilchrist Profile picture
17 Sep
COVID-19: UK vaccine update: Children 12-15

Chief Medical Officers from the UK have recommended COVID-19 vaccines for all those 12-15 ( gov.uk/government/pub… ). This would be 1 dose with a second dose determined later (spring) based on more data accrued internationally. 🧵1/4
The recent advice from the UK's Joint Committee on Vaccination and Immunisation (JCVI) did not take into account any benefits to the community or society despite finding marginally better benefits from vaccinating children 12-15. 2/4
In this case the four CMOs looked at a much wider perspective and when taking into account other details including disruption to education, protection of parents and family members, they came to the conclusion that all 12-15 should be vaccinated. 3/4
Read 4 tweets
Dr. Jeff Gilchrist Profile picture
8 Sep
COVID-19: UK decision not to universally vaccinate children 12-15

The UK's Joint Committee on Vaccination Immunisation (JCVI) recently announced they did not support universal vaccination of 12-15 year olds at this time ( gov.uk/government/new… ). 🧵1/
How did they come to a different conclusion than all the other countries who are already offering vaccines to those 12+ despite actually admitting that the benefits from the vaccine for 12-15 are "marginally greater than the potential known harms"? 2/
As usual, you need to look at the fine print and context they were using. First, they seemed to be using ICU treatment as their baseline and noted that only 2 healthy children per million need ICU care which was too small of a benefit ( washingtontimes.com/news/2021/sep/… ). 3/
Read 34 tweets
Dr. Jeff Gilchrist Profile picture
7 Sep
COVID-19: Immune antibodies vs T cells in protection

A very interesting study looked at which parts of the immune system are most important for clearing infections from the body ( science.org/doi/10.1126/sc… ). 🧵1/
The immune system has innate and adaptive immune responses ( ncbi.nlm.nih.gov/books/NBK26846/ ). The adaptive immune system remembers previous encounters with specific pathogens and destroys them when exposed again but is slow to develop on a first/primary exposure to a new pathogen. 2/
Specific clones of B and T cells have to become activated and could take a week or more before the immune responses are effective (this is why you are considered fully vaccinated 14 days after you get your dose). 3/
Read 8 tweets
Dr. Jeff Gilchrist Profile picture
21 Aug
COVID-19: Understanding efficacy when majority of hospitalized are vaccinated

I keep seeing more and more people confused about the raw # of reported COVID-19 cases or hospitalizations of vaccinated people. 🧵1/
The conclusion that some people are drawing is that this must mean the vaccines don't work. Except that they do, and work very well. The problem is with understanding the math, context, and something called Simpson's paradox which I will explain below. 2/
How can the efficacy of the vaccine vs. severe disease be strong when 60% of hospitalized in Israel are vaccinated for example? Jeffrey Morris put together an excellent article explaining all of this, which I will summarize ( covid-datascience.com/post/israeli-d… ). 3/
Read 28 tweets

Did Thread Reader help you today?

Support us! We are indie developers!

This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Too expensive? Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal Become our Patreon

Thank you for your support!

Follow Us on Twitter!

Like this author's thread?

Get emails when @jeffgilchrist has new unrolls!

Check out other threads from @jeffgilchrist!

Read all threads by @jeffgilchrist

:(