Thread by @DrTomFrieden

Herd immunity to Covid? Maybe an impossible dream. We need to reframe our approach to the pandemic and learn more, and limit the death and disruption. Here’s how. 1/thread

No one knows what will happen next in the pandemic. Longer-term predictions are just guesses. But we do know the endgame has shifted. Eradication is not possible. Even control will be difficult. We can reduce transmission and severe disease, but we can’t eliminate them. 2/

Today an FDA committee voted to recommend booster doses of Covid vaccines for people ages 65 and older and those at high risk of severe disease. Unlike Israel, they decided there is currently insufficient evidence of the need or benefit for everyone to get boosters. 3/

The situation in Israel demonstrates the challenges. Israel was an early leader in vaccinations but is now facing a big surge in Covid cases. They’ve provided a trove of important data on vaccine effectiveness, but important questions remain. 4/

Data from Israel—presented to the FDA committee today—shows that the Pfizer vaccine (the only one they’ve used) appears less protective against infection now than before. Whether that’s waning immunity or the virulence of Delta or both isn’t known with certainty. 5/

The good news is that data from Israel shows that vaccines still protect remarkably well against severe illness and death from Covid. Hospitalizations and deaths have not increased at nearly the same rate as in previous waves. 6/

One important unknown: To what extent do increasing breakthrough infections foreshadow increasing severe infections? Recent data suggest the effectiveness of Pfizer against severe disease has decreased somewhat over time among older adults during Delta. bit.ly/3Cs7BhB 7/

Does what we’re observing in Israel with the Pfizer vaccine apply to other vaccines? Not entirely clear, though the CDC data published today suggests that Moderna offers more effective and persistent protection against hospitalization than Pfizer. bit.ly/3Am7tzw 8/

Moderna uses a higher dose. It also has a 4-week not 3-week interval between doses, which probably increases efficacy. And it was approved more recently, so there’s been less time for immunity from Moderna’s vaccination to wane—if waning is a problem. 9/

If more breakthroughs are from Delta rather than waning, a dose of Delta-specific tweaked mRNA vaccines may offer better, longer-lasting protection than an additional dose of existing vaccines. But it’s not either/or. 10/

It’s crucial that we get data on risk factors for severe breakthrough. That involves transparently studying these cases to inform decisions about boosters. This is the data that scientific expert advisory groups and regulatory agencies need to make informed recommendations. 11/

Some questions the FDA committee asked:
- Whether protection against severe disease will wane in the general population
- If waning of protection is caused by time or Delta
- If boosters meaningfully strengthen protection
- Safety of boosters
- If boosters stop transmission 12/

We already know that people who are immunocompromised aren’t well protected by two doses and a third may help as part of their primary series. We may also need a different vaccine schedule or dosing for older adults. Some types of vaccines are given at 0, 1, and 6 months. 13/

Given what we know and don’t know at this point, a sensible way forward is becoming clearer based on filling our knowledge gaps, protecting the most vulnerable, and reducing the risk of new dangerous variants emerging. 14/

I agree with the FDA group that a third dose makes sense for people 65+ and at high risk. Though we aren’t certain it will be necessary or effective, it’s reasonable to conclude that it will be. Even more important is to increase vaccine uptake among these groups. 15/

We also need to consider an mRNA dose for those who initially received J&J vaccine. 16/

We MUST increase global vaccine supply through tech transfer—especially mRNA vaccines. Donations are not enough. So far, the US has failed to increase manufacturing. Neither Pfizer nor Moderna have behaved as good corporate citizens. 17/

(That’s the polite way of saying their behavior in focusing on selling boosters to rich countries and not expanding production for the rest of the world, and, in the case of Pfizer, claiming Africa can’t handle the vaccines, is egregious beyond words.) 18/

I’m disgusted by the activities of Pfizer and Moderna. I’m disappointed by the failure of the Biden Administration to scale up manufacturing. And I’m disheartened that CDC and others haven’t done better studies of risk factors for severe breakthrough. 19/

Failure to increase vaccine production is a moral failing and epidemiologically short-sighted. The US taxpayers paid for Moderna’s invention, and Moderna now has $12 billion in the bank. It’s way past time for the US to ensure Moderna shares this technology much more widely. 20/

If not:
- The US and world will be vulnerable to newer, more virulent variants that arise from uncontrolled spread
- Travel and trade will not recover
- Political instability will increase
- Millions will die unnecessarily
- The pandemic will be unnecessarily prolonged. 21/

There’s a myth there will be a vaccine glut in 2022—nonsense!
- Manufacturers missed targets by 96% in 2020
- Manufacturers (excluding China) will miss their targets by over half in 2021
- Boosters, re-vaccination, tweaked vaccines etc
- Global need >10 billion doses in 2022
22/

At current production levels, it will take YEARS to produce this. We need a step-function up, and this can only be done by stopping the current situation in which two companies hold the world hostage. 23/

We can’t rely on vaccination alone to contain Covid. Masks, testing and other measures are also necessary. But we must still increase vaccinations—our most powerful tool—around the world to prevent deaths, preserve health care, and reduce spread as much as we can. 24/

Finally, we must learn this lesson and act accordingly: Health protection and public health matter.

Microbes outnumber us, we must work together to outsmart them. 25/end