COVID-19 Vaccine Update (Green, 12/16/2020)

Okay, so often enough when I am writing these summaries, I cannot do the speaker justice with my summary; this time the ante is upped. If you haven't gotten a chance to listen to Dr. Gary Green's Grand Rounds from 12/16/2020 and you are wondering about the science behind these vaccines, please watch it. Here is the link: https://www.youtube.com/watch?v=cBTnlrcHaKU&feature=youtu.be

For those of you who prefer written word, here are my summary points:

COVID-19 is raging in the California right now, over 60,000 cases reported yesterday. In SoCo, we had a reported 606 cases yesterday-- that is more than triple our previous high from last week. Some experts have called this "the third wave", but Dr. Green referred to our current California and local surge as our "second wave" because California didn't see a surge back in April/May when NYC did (see image below).

Historical context

Dr. Green encouraged us to reflect upon the tremendous historical impact of this pandemic, comparing peak daily death rates to Pearl Harbor, D-day and 9-11, which were each ONE day events. We have had many days and days of equivalent number of deaths during 2020. 

Looking at the 1918 flu epidemic, it's important to note that the initial pandemic included THREE waves (spring, fall, winter) that spanned the first 1 1/2 years of the pandemic but that the pandemic flu strain (in the absence of a vaccine)  wreaked havoc for several years after the initial 3 waves (1921, 22, and 23, see image). Hopefully vaccination will save us from such a long tail!

Multi-pronged strategy to control COVID-19 in our communities

We should remember that management of this pandemic has several key public health pillars, which remain important. The vaccine is additive to the important strategies already being implemented. These include:

• Full PPE for healthcare workers with care of COVID patients and PUIs
• Surgical masks at all times
• Frequent hand washing
• Social distancing when possible (6 feet)
• Break room modification to avoid crowding
• Avoid carpooling or socializing outside of work/family
• Avoid social mixing (keep your bubble small)
• Vaccination

Vaccination

On 12/11/2020, the Emergency Use Authorization was approved by the FDA for the Pfizer mRNA vaccine for COVID in persons >16 years and older. On 12/17, the advisory committee is meeting to review the mRNA vaccine from Moderna for persons >18 and older. It is expected to be approved also under EUA. 

Vaccines in the pipeline

Experts agree that we need multiple different vaccines to be able to fill the world's supply. There are currently 160+ vaccines in preclinical trials, 1 (Pfizer) approved last week for EUA and a second likely to be approved within days, and . To track these vaccines, you can follow their progress at the NY Times vaccine tracker: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

What do we want a vaccine to do?

• prevent infection
• prevent illness
• prevent severity/fatality if you get sick
• prevent transmission

What is this new mRNA technology and should I trust it? It all happened so fast. . .

First of all, scientists have been working on this mRNA technology for many years, decades in fact. Both the Pfizer and the Moderna vaccine use the mRNA of the COVID-19 spike protein to provoke an immune response. You can NOT get COVID from the vaccine. While you are right, this was quite quick, it's not out of nowhere. Over the last two decades, there have been rapid improvements in vaccine creation: the SARS vaccine was created in 20 months (2003), H1N1 (2009) in just 9 months (2009), and Zika in 3.25 months (2013). The science is sound. 

How effective is the mRNA vaccine?

Both mRNA vaccines (Pfizer and Moderna) are designed to require two doses. It appears that after two doses, both vaccines are 94-95% effective. This is MUCH better than anyone could have hoped for; in fact, several months ago, the FDA said that it wouldn't consider a vaccine to be approved unless it was at least 50% effective. This is so much better than that!

See the data below from the Pfizer study in the image below. In this study of 44K people, the vaccine demonstrated 52.4% efficacy after first dose (there were 39 cases of COVID in the vaccine group and 82 in the placebo group), but 95% after the second dose, given 21 days later (162 cases in placebo group, 8 cases in the vaccinated group, none severe).

What about the vaccine side effects?

Yes, the Pfizer vaccine is a reactogenic vaccine (think Tetanus shot or Shingrix). Many folks will have a sore arm (84%). More than half will get fatigue (62.9%) and headache (55.1%), and a significant amount will get muscle aches (38.3%), joint pains (31.9%), chills (23.6%), and fever (14.2%).   The Moderna vaccine has very similar side effect profile (e.g. 90% injection site reactions and 68% fatigue, and 15% fever). Expect more side effects after the second dose than the first.

Also of note are a few unique events, including lymphadenopathy and a higher than expected rate of Bell's Palsy. Also reported in post-marketing (not during the study) are 3 events in UK and 2 in the US of anaphylactic-like reactions, almost all of which occurred in people with a history of anaphylaxis. This is being watched closely. The CDC recommends patients be observed for 15 minutes after injection to be sure they don't have such a reaction (30 minutes if you have hx of anaphylaxis). They are recommending if you have had anaphylaxis specifically to any vaccine, you should not get it at this time.

What about pregnancy and lactation?

Pregnancy and lactation were both excluded from both Pfizer and Moderna studies. However, in both studies, there were incidental pregnancies and no demonstrated adverse outcomes. The FDA says pregnancy is NOT a contraindication. ACOG and SMFM take it a step further: both recommend the vaccine in the 2nd and 3d trimester.

Are there any contraindications?

People who have had COVID-19 are recommended to get the vaccine, 90 days after infection. But, at this point, there are no known clinical contraindications. . As it is NOT a live vaccine, immunocompromised folks are safe getting it, there is no evidence of neurological side effects, folks with GBS are recommended. 

How do we get to herd immunity?

Dr. Green walked us through the notion of the basic reproduction number of a virus (R0, thought to be around 2.5-3.5 for COVID-19 under natural circumstances). He explained how both the R0 of COVID-19 AND the specific vaccine efficacy ultimately determine our ability to achieve herd immunity. 

Remember that herd immunity occurs when a large portion of a community (the herd) becomes immune to a disease, making the spread of disease from person to person unlikely. As a result the whole community is protected (not just those who are immune). For the math geeks out there, refer to this paper from the Lancet. Basically we need to get 63-75% of the population vaccinated with either of these current 94% effective vaccines to get to herd immunity. 

Final take homes:

1) Get vaccinated! 2 doses, either vaccine

2) Because this is being licensed under the emergency use authorization (EUA), vaccine is highly recommended but not mandated for all persons >16 years old

3) Moderna vaccine is likely to be approved and distributed in a matter of days (doesn't need to be kept at sub-zero temperatures, similar side effect profile, similar efficacy, may ultimately be easier to distribute to community). 

4) Getting vaccinated does NOT mean we can abandon the rest of our public health pillars. We will still continue to need to use PPE in the healthcare setting, wear masks, maintain social distancing, keep our social bubbles small, and wash our hands like our lives depend on it.