Thread by @drsanjaygupta

Most people on the planet want a vaccine right now and we got some news this week that the process is speeding along. Getting a vaccine approved (or authorized) quickly will be critical, but how fast is too fast? Let’s take a look.(1/20)
cnn.com/2020/09/13/hea…

Remember EUA - stands for Emergency Use Authorization - and permits the FDA to allow the use of unapproved drugs and products to manage a public health emergency. These terms are important. These products would be “authorized” but not yet “approved.”(2/20)
fda.gov/emergency-prep…

For this pandemic - hundreds of EUAs have been issued for diagnostic tests but just two are currently being used for therapeutics - the antiviral remdesivir and convalescent plasma - donated antibodies from Covid-19 survivors. (3/20)

An EUA for hydroxychloroquine was issued in March. But as larger studies were conducted, no benefit was found & there was evidence it could cause harm. The FDA revoked the EUA on 6/15. (4/20)
fda.gov/media/138945/d…

The EUA standard for a vaccine has to be especially high. Why? It’s given to healthy people to prevent illness, as opposed to sick people with no alternatives. And, with vaccines, there is an alternative - masks and physically distancing, which are proven to work. (5/20)

I believe strongly in vaccines and what they can do for public health. But we need to trust that these vaccines are safe and effective and undergo the proper scientific and regulatory oversight. And that takes time to get it right. (6/20)

In Phase 3, ~ 30K ppl are randomized into vaccinated and placebo groups. The hope is to see an “efficacy signal,” -- the placebo group becoming infected at a faster rate than the vaccinated group. Keep in mind: The current US infection rate is around 1/10K people per day (7/20)

Moncef Slaoui, chief advisor to Operation Warp Speed, told me the sort of “efficacy signal” they would like: ~110 infections in the placebo group, and no more than ~50 infections in vaccinated group. Doing the math, that means the signal would take around 4 months to occur (8/20)

Another reason to go slow: safety Moncef Slaoui also told me most adverse effects occur within 42 days of vaccination, so the phase 3 trials won’t likely be considered complete until both shots have been given and then volunteers are monitored for that time. (9/20)

The goal is to avoid a catastrophe like the vaccination effort of 1976. Back then, a new strain of swine flu was found. Worried that it might be repeat of 1918, a vaccination program was quickly started. (10/20) wwwnc.cdc.gov/eid/article/12…

But by December 1976, fewer than 40 million people had been vaccinated and no outbreak ever occurred. There were, however, more than 50 cases of a neurological disorder called Guillain-Barre syndrome. (11/20)
cnn.com/2020/04/24/hea…

While there’s never been a definitive link between Guillain-Barre and that vaccination, the CDC did find 1 case of Gullain-Barre for every 100,000 people who received the swine flu vaccine and ended the vaccine program. (12/20)

A New York Times op-ed called it “The Swine Flu Fiasco” and said that “Washington’s energies” had sickened many because of their inability to put “biological reality before political expediency.” (13/20)
timesmachine.nytimes.com/timesmachine/1…

In 2017, a campaign to vaccinate nearly a million kids from the mosquito-borne disease Dengue in the Philippines ended after 10 children died. Officials had been warned that the vaccine should only be used in people who had already been infected. (14/20)

Why? Because Dengue is actually caused by four different viruses and in this case, vaccinating people who had never been infected, raises the risk of complications if they are then infected by a different strain. (15/20)
cnn.com/2017/12/04/hea…

When the public perceives politics is before science, it breaks down public trust. And that trust is as important as the scientific evidence. You need both to achieve vaccine effectiveness. (16/20)

There are some lessons from past pandemics. During the 2009 H1N1 pandemic, a poll revealed just under 9% of people said they would be willing to get an unapproved (only authorized) vaccine. (17/20)

In that same poll, they found if a simple fact sheet was provided - 57% of people would get it. If given directly and explained by their own doctor, willingness to use a vaccine under EUA jumped to 68% (18/20)
ncbi.nlm.nih.gov/pmc/articles/P…

A recent Kaiser poll found that 62% of Americans are worried that political pressure will cause the FDA to rush approval of a vaccine. (19/20)

We can achieve “community immunity” once most of us are vaccinated -- but we can only do that if we can trust that we have a safe, effective and trusted vaccine. In the meantime, the alternative can still keep us safe - a few more months of masks and distancing. (20/20)