US Vaccine Progress: Over 50% of the eligible population (140 million out of ~265 million) have had at least 1 dose of COVID vaccine.

Herd Immunity (80%):
125 million to go with vaccine alone.
Only 70 million more to go if we also include people who have had COVID & recovered
Two assumptions: I'm assuming ~30% of children & adults have had COVID & recovered (30 million confirmed; 60 million unconfirmed).

Also assuming all people who got need 2nd dose to be fully vaccinated will eventually get it (recognizing this is not happening & we need to fix it)
I'd prefer 125 million more people as the minimum target for vaccination. But suspect cases will decrease quite a bit if we get 70 million more vaccinated.

The last 50 million will be hard. We will need to overcome vaccine hesitancy through people they trust.
The one issue we need to be cautious of that may affect the calculations is the extent of protection current vaccines offer against bad variants. I am still confident that current vaccines will protect from severe disease from variants. But wish we had more data.
The other issue is duration of protection offered by the current vaccines. We hope that the duration is long. Even years. But need more data which of course means we need time.

My guess is that we will need periodic boosters.
Other issues to keep in mind:

1) Efficacy of vaccines in immunosuppressed people

2) Efficacy of vaccine in the face of high viral dose exposures. Studying infection patterns following vaccination in healthcare workers vs age matched general population will help with this.

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More from @VincentRK

28 Apr
Viral dose is an important factor in severity of COVID. As India waits for vaccines, I urge people in India to wear masks and avoid crowds. This is the best way to reduce viral dose, and repeated exposures.

Lower viral dose will reduce severity of illness. And reduce deaths.
For over a year we have been saying that masks play a role in reducing viral dose, and at this point I'm more convinced than ever before. Have to unearth old tweets and graphics.
Severity of COVID is influenced by many factors, but unfortunately most of these are not in our control. Not easily "changeable": age, obesity, comorbidities, type of mutant variant, genetics, etc.

The one factor that is in our control is reducing viral dose at exposure.
Read 8 tweets
27 Apr
As COVID rips through India, the nearly 100,000 doctors of Indian origin who are in the US feel both helpless & determined to help at the same time.

Most of us have close family in India. Every few hours we get calls about some friend or relative who's very ill with COVID.
The scale of the pandemic is hard to describe in words. This figure is a serious underestimate.
We are grateful that the US will send vaccines, vaccine raw materials, test kits, emergency supplies, and more. India needs all the help it can get.
Read 6 tweets
24 Apr
This is a plea to the US government to help India. What you can do:

-Help with Oxygen & Oxygen generators
-Release Astra Zeneca vaccine supplies
-Lift the export ban & send them raw materials for vaccines

As bad as this looks. It's 10 times worse. The Indian people need you.
This is not only the right thing to do. It is also wise. If this absolutely stunning and dramatic spike is due to a bad COVID variant, then it is going to affect us.

It will be self defeating to crush COVID only to let a bad COVID variant get us again.

Please act urgently.
It is not everyday that a request like this goes out. On April 16 new cases were 180,000 per day.

It is a week since this request. It is now 300,000 new cases per day. Urgent will be an understatement. @adarpoonawalla
Read 6 tweets
24 Apr
Studies were reporting 40-50% seroprevalence in big cities in India even by December. The same cities (eg. Delhi, Mumbai, Chennai) are now totally overwhelmed with COVID.

What does this mean? How could this even happen?…

@SmritiMallapaty @nature
First, sampling in big cities could have been wrong and didn't estimate the true seroprevalence accurately even within each city, let alone India.
Second, even if 50% seroprevalence was true, that still leaves 50%.

50% of India still means 650 million people susceptible. Twice the size of the US population.
Read 7 tweets
23 Apr
Updated Risk of vaccine related cerebral venous sinus (or splanchnic vein) thrombosis associated with low platelets

Astra Zeneca
1 in 100,000 (EU)
1 in 250,000 (UK)

1 in 500,000 overall.
1 in 150,000 for women age 18-49.

No risk seen with Moderna or Pfizer vaccines.
The risks are extremely low. Awaiting CDC panel recommendations on J&J pause.
The pause was justified. To determine the numerator & the denominator. CDC panel has voted today to resume vaccinations with the J&J vaccine.…
Read 6 tweets
22 Apr
One year had gone by. We thought that given India's population and crowding, that the number and severity of COVID was inexplicably low.

Well that part was true. But not because of a miracle or massive undercounting. It was sadly because the worst was yet to come. A crisis.
Either lockdowns and restrictions had worked really well, and once everything broke free after November, COVID did what it does.


New dangerous mutants evolved.


Both happened together.

End Result: The present crisis.

In this time of crisis & desperation, 2 problems must be dealt with simultaneously.

1) Care of patients with COVID in a sensible way that optimizes the use of scarce resources & minimizes loss of life

2) Reduce new cases by masking, distancing, & rapid vaccination
Read 7 tweets

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