COVID-19: Infection Spikes, Vaccine Rates, and Variants, Explained

Published on: Apr 29, 2021fb-roundtwitter-roundemail-round
Woman receives the Johnson & Johnson COVID-19 vaccine.Getty Images

The US is reportedly administering vaccines nearly five times faster than the rest of the world. And as every state has opened up their vaccine eligibility to all adults, more than 3 million Americans are getting a shot every day. Now, it appears that the US is coming out of a spike in cases from earlier in the spring. But more than 50,000 new cases are still being reported daily (prior to this, that number was upwards of 60,000).

But aren't vaccine rates going up?

Yup. But health officials say younger people have contributed to the high number of cases. According to data from the CDC, more than 80% of people ages 29 and below are unvaccinated (though that number could change as more Americans – especially younger people – continue to get vaccinated).

In the meantime, outbreaks driven by younger people have been attributed in part to school openings (specifically “youth sports and extracurricular activities” according to the CDC director) and COVID fatigue.

That’s the burnout we’re feeling from dealing with the stress and uncertainty around the pandemic. COVID fatigue can cause people to let their guard down (think: being less diligent about wearing a mask, getting together with larger groups). Recent data from Gallup shows that only 35% of Americans are very or somewhat worried about contracting the virus – the lowest number since last April (it was 57% back then).

Another area of concern: coronavirus variants.

Tell me more.

Variants happen when a virus’s genes change or mutate. The word ‘mutate’ might sound scary, but it’s actually normal. As the virus spreads, it makes copies of itself. And sometimes, not all of the same instructions make it into the new copy. So it becomes a different version (aka a new strain or variant). Typically mutations aren’t a big deal because they don’t always change how a virus behaves. But the CDC says there are a handful of variants “of concern.” Here’s what you need to know about them… 

  • B117. Aka the UK variant, first detected there in September. It’s spread to dozens of countries, and as of April it’s become the dominant strain in the US. It’s believed to be about 50% more contagious. Scientists initially thought it could be more deadly, but a recent study shows that it’s not likely to cause more serious illness or death. Experts say that the vaccines currently available seem to offer good protection against B117.

  • B1351. Aka the South Africa variant, first detected there in October. It’s now spread to at least 48 countries and more than 30 states. In January, experts said it’s about 50% more contagious. Unclear if B1351 is more lethal than other strains. There are concerns that vaccines may not be as effective when it comes to this variant. Researchers in Israel found that it could break through the Pfizer vaccine – which is 95% effective. And there’s some evidence that it may be able to reinfect people who’ve already had COVID-19.

  • P1. Aka the Brazil variant, first detected in January after four travelers went from Brazil to Japan. And has now been found in more than two dozen countries and at least 25 states. It’s helping fuel a surge of cases in Brazil and spreading to other areas of South America. The variant is believed to be more contagious and data shows it’s more likely to reinfect people. But there are a few things we don’t know, like: how deadly it is and how vaccines work against it.

  • B1427/B1429. Aka the California variant, first detected there in late 2020. This variant has been documented across the US and in a number of countries, and it may have helped create a surge in cases in CA during the winter. The CDC says it’s about 20% more transmissible than the original COVID-19 strain, but it apparently doesn’t seem to spread as fast as variants like B117. Vaccines reportedly seem to be effective against it.

But these aren’t the only variants out there. The CDC is keeping a close eye on another one from Brazil, as well as from NYC. Meanwhile, another variant first detected in India has started to get some attention around the world: B1617. India's health care system is crumbling as it deals with an unprecedented surge in cases (think: consecutive days of 300,000 new cases per day), leading to oxygen and hospital bed shortages. And variants (among other things like large gatherings) have contributed to the spike, but it’s unclear if B1617 is the main culprit.


The US is in a critical period of combating the coronavirus. While vaccination rates tick up, so are new infection rates. And as scientists learn more about variants, it's as important as ever to keep practicing the basics – wash your hands, social distance, and mask up.

Last updated on April 29 – Updated to include details on India's second wave of COVID-19 cases, as well as updates to COVID-19 cases and variants in the US.

Skimm'd by Maria Martinolich and Kamini Ramdeen

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