The Science You Need To Make Your COVID-19 Decisions

Author: News Media
December 28, 2021

We’re tracking the research so you don’t have to.

By Maggie Koerth FIVETHIRTYEIGHT.com December 21, 2021

https://projects.fivethirtyeight.com/covid-19-updates/#question-2

If there’s one thing we’ve learned since March 2020, it’s that pandemics are all about hard decisions. It’s hard to keep track of the information that helps us make those choices — let alone notice or remember when new science and expert recommendations come along. At FiveThirtyEight, we want to help. We’ve read the science and have come up with broad assumptions you can make based on where the evidence is. When the science changes, so will the assumptions: We’ll be updating this page regularly as new research is published.

We think these assumptions will help you more easily make decisions for yourself and your family. (But do let us know if there are risk-assessment questions you think we’re leaving out.) We want this tool to be something that helps take the stress out of decision-making so that you can worry more about the best way to live and less about the virus.

What should I do to protect myself from omicron, the World Health Organization’s newest COVID-19 variant of concern?

WHAT YOU CAN ASSUME

The answer depends a lot on what you’re already doing. If you’re someone who is already vaccinated, wears a mask in public places, avoids large crowds and uses tools like rapid tests before big gatherings there’s not a lot you can change. (Though it will likely have some effects on how you do the things you already do.) Preliminary data suggests boosters are more important in the face of omicron, so you should get one of those. And if you have stopped masking, eased your social distancing protocols, or never even got vaccinated to begin with, understand that scientists believe omicron has us poised for a big wave of new cases — on top of the still high wave of delta cases already happening. Omicron makes primary vaccination more important than ever because those vaccines mean reducing your now-increased chances of contracting a severe, life-threatening illness.

WHY WE MAKE THESE ASSUMPTIONS

  • Omicron is significantly more transmissible than other variants of COVID-19 and seems to evade primary vaccine doses at higher rates.
  • It’s not yet clear whether omicron makes people less severely ill.
  • Preventing new variants is largely a problem for scientists and politicians, not individuals.
  • Travel bans on specific countries aren’t effective tools for protection against a new variant.

Who benefits from a booster shot and when should we get one?

WHAT YOU CAN ASSUME

The Centers for Disease Control and Prevention now says everyone over the age of 18 should get a booster shot either six months after their initial Pfizer-BioNTech or Moderna vaccination series was complete, or two months after receiving their original Johnson & Johnson vaccination. People over 65, people who initially received the Johnson & Johnson vaccine and those with health complications that increase their risks of contracting or being harmed by COVID-19 stand to gain the most. But the omicron variant has made boosters more critical for maintaining effectiveness for everyone.

WHY WE MAKE THESE ASSUMPTIONS
  • Vaccines are less effective at preventing infection and transmission than they once were.
  • Preliminary data suggests the new omicron variant can evade primary vaccine doses.
  • Older people get a much bigger benefit from boosters than younger people.
  • There seems to be a lot of uncertainty among scientists about how we should think about boosters going forward.

What test should I take if I’ve been exposed to COVID-19?

WHAT YOU CAN ASSUME

Instant at-home tests and PCR tests can both be useful and continue to be effective at identifying cases of omicron variant illness. But it matters when you’re using them and what you’re trying to do, and omicron should change some of your testing procedures.

WHY WE MAKE THESE ASSUMPTIONS
  • The instant at-home tests are rated as less sensitive overall.
  • The instant at-home tests are about as sensitive as PCR tests for the time period when an infected person is most likely to be contagious.
  • If you choose at-home tests, you should test more than once.
  • PCR tests will still work to detect omicron. At-home tests kits work, as well, but if you’re testing so you can see others safely, you should be testing closer to the time of your gathering.

Do masks protect you and others from COVID-19?

WHAT YOU CAN ASSUME

They do. But effectiveness depends on the type of mask you and those around you are wearing. There is not yet omicron-specific data about mask effectiveness. The CDC recommends everyone over the age of 2 — regardless of vaccination status — wear a mask in public, indoor places when COVID transmission rates are substantial or high. Also, you can use HSA and FSA money to buy high-quality masks.

WHY WE MAKE THESE ASSUMPTIONS
  • There’s been a lot of research on mask effectiveness since the start of the pandemic.
  • Your cloth mask is not as effective as you probably think it is.

Should I get my child vaccinated?

WHAT YOU CAN ASSUME

Yes. Everyone (kids included) is more likely to catch COVID-19 than they were earlier this year. The delta variant is more contagious, though it doesn’t seem to be worse for kids than for adults, either in likelihood of transmission or severity of illness. Kids who spend their time around vaccinated adults and teens are at lower risk, but the benefits of vaccinating kids outweigh the risks.

WHY WE MAKE THESE ASSUMPTIONS
  • The benefits of vaccinating kids outweigh the risks.▹ Read more
  • Real-world data shows cases and hospitalizations among U.S. children rose quickly with delta.▹ Read more
  • Delta is more contagious than earlier variants.▹ Read more
  • Vaccinating those who can be vaccinated protects people who can’t.

How long do I have to quarantine if I’ve been in contact with someone who has COVID-19?

WHAT WE CAN ASSUME

It’s still best to follow the CDC guidelines, which currently recommend a quarantine for 14 days (from the point of exposure) for unvaccinated people. They also recommend testing at least five days after exposure. Vaccinated people, according to the CDC, can skip quarantine if they show no symptoms, but they should still be tested three to five days after contact and wear a mask indoors in public until they have the results. (The CDC also says there are ways to shorten the quarantine period.) It’s worth noting that U.K. policy has changed in the wake of omicron, and now recommends daily rapid tests for seven days after exposure and avoiding contact with others — even for double-vaccinated people.

WHY WE MAKE THESE ASSUMPTIONS
  • Different states and agencies offer different guidelines, but they’re all based on the same science as the CDC’s.▹ Read more
  • Differences and changes don’t mean it’s just all arbitrary.

How likely am I to contract and spread COVID-19 if I’m vaccinated?

WHAT WE CAN ASSUME

Breakthrough cases, even with the reduced effectiveness of vaccines against the delta variant, are rare. That’s especially true for symptomatic cases. The newer omicron variant is changing this calculus, however, and to be just as safe against the new variant probably requires a booster shot. . If you do catch COVID-19 but you are vaccinated, you can spread it but are probably contagious for a shorter period of time — and are probably less likely than an unvaccinated person to spread it.

WHY WE MAKE THESE ASSUMPTIONS
  • Vaccinated people are much less likely to catch COVID-19.
  • Vaccinated people are probably more likely to catch the omicron variant than delta.
  • Real-world cases show vaccinated people can spread the disease.
  • But the evidence doesn’t suggest that vaccinated people are as likely as the unvaccinated to spread COVID-19.

How likely am I to catch COVID-19 outside?

WHAT CAN WE ASSUME

It is possible for the delta variant of COVID-19 to spread outside, even among the vaccinated. That said, outdoor transmission is probably still unlikely if you avoid crowds. If you’re vaccinated and not all up in one another’s business, outdoor transmission shouldn’t be a major fear. There’s not yet evidence about whether the new omicron variant changes any of this. Of the first 43 U.S. cases of omicron that the CDC has full documentation for, none were associated with casual outdoor contact that would have been considered low-risk for the delta variant.

WHY WE MAKE THESE ASSUMPTIONS
  • Pre-delta research suggested risks of outdoor transmission were small.
  • There’s not much delta-specific research, but evidence suggests it’s still fairly safe to be outside together.
  • However, all outdoor contact is not the same

What do we know about the rate of long COVID?

WHAT YOU CAN ASSUME

Long COVID is real, and it is possible for anyone to get it. That includes kids and vaccinated people — although both are probably less likely to end up with long COVID than unvaccinated adults. But we don’t really know the rates, largely because there still isn’t any universal definition of what does and doesn’t count as long COVID. Be cautious with assuming anything too precise from very imprecise research. There is not yet information available about whether the omicron variant affects long COVID risk.

WHY WE MAKE THESE ASSUMPTIONS
  • Researchers say most studies of long COVID are still frustratingly vague, flawed and hard to compare with one another.▹ Read more
  • Long COVID is real.▹ Read more
  • Preliminary research suggests long COVID is less likely to occur in patients who were previously vaccinated and in patients under age 10.

For Help and Support

Design and development by Emily Scherer, Julia Wolfe and Elena Mejía. Additional reporting by Anna Rothschild. Story editing by Chadwick Matlin. Copy editing by Andrew Mangan and Curtis Yee.

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