Thread by @CMichaelGibson

Why we might not get a coronavirus vaccine | The Guardian theguardian.com/world/2020/may…

The Dengue fever virus was discovered in 1943 and it was not until last year that the first vaccine was approved

30 years after scientists isolated HIV, there is no vaccine

#COVID19 is a #coronavirus & this type of virus does not tend to trigger long-lasting immunity.

About 1 out of 4 common colds are caused by a coronavirus, but because immunity fades so quickly, people get reinfected year after year.

There is no vaccine to the common cold.

Oxford researchers also found that in people who recovered from #Covid19 the levels of IgG antibodies – the ones that give you longer-lasting immunity – rose a lot in the first month but then began to fall again after that.

Here is the link to that pre-print showing the fall in IgG antibodies after a month medrxiv.org/content/10.110…

Researchers have also recently reported that those people who tested positive by nasal swab but who were not sick enough to go to the hospital did not develop a lot of antibodies raising the question: do you only become immune if you were really sick biorxiv.org/content/10.110…

The flu and HIV mutate or change quickly making it hard to develop a vaccine. #covid19 changes less quickly than them BUT there are slower changes to its surface “spike” proteins which are the target of vaccines so any vaccine could become outdated.

One worry is “antibody-induced enhancement” where the vaccine causes antibodies to be made that make future infections worse.

It’s a “Goldilocks” problem:

Too weak a response doesn’t give immunity

Too strong a response may attack the body

We need a “just right” vaccine

The good news is that the Moderna vaccine produced antibody levels that were similar to that in recovering patients which sounds “Goldilocks” like, but we don’t know enough about the T cells that attack the virus yet investors.modernatx.com/news-releases/…

We may need to settle for partial success:

A different vaccine from Oxford University than the one being tested did not stop monkeys contracting the virus, but it did reduce the risk of pneumonia, which is a major cause of death in human coronavirus patients.

This sounds good, right?

The problem is in these people who survive the virus keeps reproducing and this increases the chances of mutations and emergence of new strains and resistance and that is bad.

For this reason it is better to kill the virus than allow it to live.

It may (likely in my mind) require a one two punch: a “Goldilocks” like vaccine that allows you to survive and additional anti virals that kill the virus in the body so it doesn’t live to infect another person & become resistant.

We need a global approach to vaccination. If any one region continues to be infected, the whole world runs the risk of infection.

One person’s health can affect everyone’s health ...

Our biggest challenge may not be science after all ...

Science is easy, people and politics are hard ... #cmgsays

I remain cautiously optimistic about the science. Defeating this virus will likely require multiple drugs (vaccines, antivirals, antibodies etc.).

The bigger challenge than the virus is, as always, us ... #cmgsays