Vaccine FAQ

As vaccines start rolling out and everyone has lots of questions about the different vaccines, I thought I’d write something up that tries to compile some useful information for all my friends. Whether you just got vaccinated, are about to get one, or waiting for it to be available in your area, this should hopefully help you navigate that!

Where I’m Getting My Info

I’ve been keeping up with developments in the pandemic pretty closely, almost daily, by following leading epidemiologists and virologists on Twitter, where they discuss each new study as it comes out. This is where I get most of my information. I’ve also linked select articles and videos that I feel accurately capture what the leading epidemiologists are saying. There are many articles that cite preprint studies that have not been peer reviewed yet, cite low quality studies or just misrepresent the findings of studies to get a more interesting headline, so I’ve found that reading news articles is not the best way to stay informed.

If I’m incorrect about any of this, please let me know and I’ll try to correct it. I’m not an epidemiologist or virologist, just someone who has been trying to stay informed!

You can check my twitter to see who I’ve been following and some retweets. This is pretty much the only thing I use Twitter for and is the only reason I’m on there.

Which Vaccine Is Best / Do They Work Against Variants?

Before I get into the differences, if you are only able to get a particular vaccine, that vaccine is far better than no vaccine. This is because ALL the vaccines are very good at preventing death and severe cases of COVID. See this tweet with a table showing the number of deaths recorded in each vaccine trial:

Read this wonderful piece by Zeynep Tufekci that elaborates and the follow-up piece as well. She writes for The Atlantic and has been doing wonderful reporting throughout the whole pandemic and explains this better than I could, but the short version is that any vaccine is better than none.

That being said, some vaccines appear to be better against variants (especially the South African B.1.351 and Brazilian P.1) than others:

• Good against variants: Pfizer, Moderna, J&J, Novavax
• Not as good against variants: AstraZeneca, Sputnik, Sinovac, Sinopharm

Source: [1, 2, 3]

Vaccines do tend to be less effective against the new variants but especially the ‘good against variants’ category above are still quite effective in preventing even mild disease, and very good against severe disease or death.

The latest research from Israel suggests that for at least the Pfizer vaccine, variants are more likely to ‘break-through’ during partial immunity, but after 14 days post 2nd dose, high effectiveness kicks in [tweet, study]. This is currently being misreported in the media as ‘Pfizer vaccine may be less effective against some variants’ which is quite misleading. See tweet.

75% Effectiveness Means It Doesn’t Work 25% Of The Time, Right?

I think people are unsure what the % effectiveness number means. Does it mean the other people are left unprotected? No, not quite.

The trials measured as their endpoint, any symptomatic disease. How many less cases of symptomatic disease were there in the vaccine group compared to the control group, that is what the percentage represents.

The part of the story that’s missing in the simple efficacy number, is how bad were the symptoms for the 25% (or whatever leftover percentage) that did get symptoms. Did they get severe symptoms? Were they hospitalized? Did they die? The data shows that for all of these other outcomes, the vaccine diminished severity across the board. So even if you get the vaccine and get COVID, you will likely have a far less severe outcome than you would have without the vaccine.

Again, I’ll point you to Zeynep Tufekci to learn more.

How Soon After The Vaccine Am I Immune?

The CDC says, 2 weeks after the last dose of your vaccine (second for 2-dose, first for 1-dose). [Source]

I would suggest looking at the Stage 3 trial for the vaccine you are getting and look at how long after the last dose vaccine efficacy was evaluated. This is the time interval for which the efficacy rate was actually measured and proven, so any date before that could have a somewhat or even significantly lower efficacy. This is:

• Pfizer: 7 days after second dose [Source]
• Moderna: 14 days after second dose [Source]
• J&J: 28 days after dose [Source]

Please note: I could be wrong about this, so please feel free to go with the CDC’s 2 week recommendation. To me, this approach makes more sense though.

Are The mRNA Vaccines Risky or Dangerous?

Probably not. Here’s a video explaining how vaccines work and how the mRNA ones differ from them:

Last year, I was skeptical about the new kind of vaccines too, but given the trials they’ve conducted I feel pretty confident in them and in fact have already received my first dose of the Pfizer vaccine.

This is a new type of vaccine though, so if you have concerns, I’d recommend getting the J&J vaccine or another that uses a more well understood and long used method of vaccination.

Will The Vaccines Cause Me To <Blank>? — eg. Get Blood Clots

No, probably not. There are many questions around what the COVID vaccines might do or cause, and most of what I’ve seen has been unfounded. Almost all the vaccines have been found to be very safe and had no safety issues. If you have a history of allergic reactions, talk to your doctor. The rate of allergic reactions to the vaccines is very low though regardless.

A caveat to this is the potential clotting issue with the AstraZeneca vaccine. This story is still developing, and the latest data suggests there might be a very rare reaction causing blood clots. The odds of this are very low, around 4 in 1 million [Source]. For reference, the odds of getting hit by lightning are 1 in a million.

Canada, the UK and some other countries have restricted this vaccine to only older age groups. Why? The risk for younger age groups of dying from coronavirus is quite low, and so that risk when weighed against the even lower risk of a clotting issue with the vaccine may not be worth it. However, for older people who at far greater risk from COVID, the very low chance of this reaction does stand up to the COVID risk. Source: [1, 2]

Update (April 14th): There now seems to be a similar though even more rare risk with the J&J vaccine. Currently, the risk appears to be less than 1 in a million chance (6 in 6.8 million), however this could change with more investigation. Source: [1, 2, 3]

Will I Get Sick When I Get The Vaccine?

The COVID vaccines are known to have side-effects that mimic a mild flu for a day or two. This can include a headache, aches, chills, and fever in some cases. None of this is a cause for concern. It will go away in a day or two. This is mostly the case with the mRNA vaccines, specifically with the second dose, and just an indication that the vaccine is working. It does not mean you got COVID from the vaccine. You cannot get COVID from the vaccine. Stay hydrated and rest! Reach out to your doctor if you are concerned.

Feeling sick for a day or two is most definitely worth immunity from COVID. You would likely get far sicker from COVID and also have a chance of developing long COVID which is prolonged symptoms for months. This should not be a reason to not get the vaccine.

My first vaccine dose (Pfizer): I didn’t really feel the needle go in at all so I was slightly paranoid that I didn’t even get the vaccine. A couple of hours later my arm felt a bit sore. This lasted for a day or two. On the second day I felt pretty tired at night but this could have just been from a hard day at work.

My second vaccine dose (Update April 16th): I got my second dose earlier this week in the evening. On the first day (Day 0), I felt no different. The next morning (Day 1) I woke up feeling tired, like I had worked out a lot the previous day. A few hours later, I felt aches and like I was coming down with something. The rest of the day, I got chills off and on aches and felt rather flu-like. When I woke up the next morning (Day 2), the aches and chills were gone and I just felt tired. The following day (Day 3), I was good as new!

Here’s a video explaining vaccine side-effects in more detail, if that’s helpful for you.

Isn’t The J&J Vaccine Worse Than Pfizer/Moderna?

The J&J vaccine efficacy is 66.3% overall and 74.4% in the US which is less than the 94–95% of the mRNA Pfizer and Moderna Vaccines, so it’s worse right? Not necessarily.

The Pfizer and Moderna vaccines conducted their Phase 3 trials last summer, when there were no new problematic variants circulating and so tested under ‘easier’ circumstances. The Johnson & Johnson vaccine, on the other hand, had trials with those variants in the picture and in countries where they were prevalent like South Africa. Despite this, the J&J vaccine still shows good efficacy numbers.

Without running new studies under the exact same circumstances, it’s impossible to say how well Pfizer and Modern compare to J&J. It’s possible their efficacy could have dipped even more than J&J’s did against the variants.

Here’s a video explanation, which some may find helpful.

Efficacy Table

Please see ‘Isn’t The J&J Vaccine Worse Than Pfizer/Moderna’ before reading this table. J&J is far more effective than this table would make it seem, and AstraZeneca and Sputnik are not good against variants which this table does not factor in.

[Source]

What Vaccines Are Available In My Country?

This is mostly sourced from friends in various countries so please correct me if I’m wrong here. If you have information about the vaccines available in your country, let me know and I can add it here!

United States: Pfizer, Moderna, J&J (halted), Novavax (expected in May)

Canada: Pfizer, Moderna, AstraZeneca, J&J (expected end April) — delayed second dose by several months

UK: AstraZeneca, Pfizer, Moderna (April) — Delayed second dose by several months

Pakistan: Sputnik, Sinopharm, CanSino

How Do I Get A Vaccine Appointment in the US?

NY State: As of April 6th, everyone 16 and older is eligible for the vaccine.

California: April 15th, everyone 16 and older is eligible for the vaccine.

Other States: Check online! Every state has announced their plans for full rollout of the vaccine. Biden has instructed states to make all adults eligible by April 19th. [Source]

• Walgreens: https://www.walgreens.com/findcare/vaccination/covid-19
• CVS: https://www.cvs.com/immunizations/covid-19-vaccine
• Rite Aid: https://www.riteaid.com/covid-19
• Vaccine Finder: https://vaccinefinder.org/
• New York only: https://am-i-eligible.covid19vaccine.health.ny.gov/
• NYC only: https://nycvaccinelist.com/

Once I’m Vaccinated, What Does That Mean?

Before getting into this, what’s very clear is interactions between fully vaccinated individuals are very safe. So if you and your friends, parents or grandparents are all fully vaccinated, you should be able to do any activity together. Here’s the CDC’s guidance for vaccinated people.

1) Can I Transmit The Virus Even If I’m Immune?

The vaccine trials measured symptomatic disease. ‘Did the people who got the vaccine, show symptoms of COVID?’. They did not measure if those people were able to infect others with COVID. This is why you might see articles saying you still have to mask and isolate even if you’re vaccinated. We don’t know for sure how well the vaccines prevent you from transmitting to others.

There is growing evidence that the mRNA vaccines are very good at preventing transmission [1, 2]. The question then is, how good? Maybe even as high as the efficacy number (~80–95%) but we can’t say for sure.

And what about the other vaccines? We don’t know for sure yet.

How is it possible for you to transmit after being vaccinated? Your body can get infected with COVID, fight it off so you don’t get symptoms, but still be able to infect others because you carry the virus. If however, the vaccine greatly diminishes viral load in people that are vaccinated, they might also not be able to transmit the virus. The latter seems to be likely for at least some vaccines. See tweet.

2) Is It Okay To Go Back To Normal After I’m Vaccinated?

This likely depends on the case counts in your region. Realistically though, I think people will start resuming more normal activities as they get vaccinated, so this is a personal decision.

Here in New York, we haven’t seen case counts drop too much after winter surge. On the day of writing this, there are ~6700 new cases in NY State and ~3300 new cases in NYC. It’s also up to you to decide what you’re comfortable with and if you have the patience to keep up precautions for longer.

What happens if as people start getting vaccinated, everyone starts having huge gatherings with vaccinated and unvaccinated people, and large amounts of virus circulating? Well, if we have large amounts of virus circulating, that means a lot of opportunity for random mutations in the virus. On top of that, we add in vaccines, and we’ve created an environment with a strong selective pressure for vaccine avoidance. Both of these combined might be a recipe for variants that can beat the vaccines.

This is likely why I see a lot of articles saying that health officials are urging people to remain careful as vaccines are rolling out and wait for case counts to come down. I left this question for the end because I think what’s most important is getting everyone the information they need about getting vaccinated rather than telling them how they should live their lives after.

I Still Can’t Decide Which Vaccine To Get, Help

A lot of people will not have the option to pick between lots of vaccines. In that case, getting whichever vaccine you have access to is much better than waiting a long time for the ‘best’ one! For those that have a lot of options:

• Can you get one of the vaccines 2 weeks or 1 month sooner than the others? Get that one.
• Is only one of the vaccines you can get in the ‘good against variants’ group? Get that one.
• Are all the vaccines you can get in the ‘not as good against variants’ group? Get the one with highest efficacy (from the table).
• Are you concerned about the new mRNA vaccines? Get J&J. (or any that’s not Pfizer or Moderna, those are the mRNA ones)
• Update (April 14th): Are you concerned about risk of blood clots? Get Pfizer or Moderna. (not AstraZeneca, J&J, Sputnik V or CanSino which are all adenovirus vector based and likely share this risk)
• Do you want just 1 dose and to be done with it? Get J&J.
• Do you want the shortest time from first dose to immunity? J&J or Pfizer, 28 days to immunity. Moderna is 42 days. For others, you’ll have to check time between doses and time till immunity, and add them up.
• Do you want maximum protection? Pfizer or Moderna. J&J a close second. Novavax when it’s available.

Thank You

If you made it this far, thank you for reading! I hope this has made some of your decisions about which vaccine to get and what to do after, easier.

If you have other questions that I didn’t answer, feel free to reach out and I’ll do my best to answer and incorporate it back into this.