Thinking of skipping your second COVID-19 vaccine shot? Here’s why you shouldn’t (video)


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The Centers for Disease Control and Prevention (CDC) has recommended COVID-19 vaccine booster shots starting in September, but millions of Americans still don’t have their second dose.

According to recent data from the CDC, about 15 million Americans who got one dose of the Pfizer or Moderna vaccines haven’t gotten their second shot.


Health experts say it’s important to get your second shot to maximize protection against the COVID-19 Delta variant.

The importance of getting both shots is even more evident as the highly contagious Delta variant spreads rapidly through California and the rest of the country. The UC Davis Health Emergency Department has seen a significant impact.

The reasons for avoiding the second dose vary, from the misconception that one shot is sufficient to concerns about side effects.

According to Dean Blumberg, chief of pediatric infectious diseases at UC Davis Children’s Hospital, the second dose is important for two main reasons.

  1. Getting a second vaccine dose boosts your immunity.
  2. Getting a second dose results in longer lasting immunity.

Researchers at Cornell University and Boston Children’s Hospital found that 20% of Americans surveyed believed they were strongly protected after just the first dose. Another 36% said they didn’t know the amount of protection the vaccines provided.

A recent study from the CDC looked at people 65 and older, finding that protection increased from 64% to 94% after full vaccination.

“Would you rather have 64% or 94% protection?” asked Blumberg. “94% sounds a lot better to me.”

Another major reason some say they skipped getting the second dose? Concerns about side effects, which are more common after the second dose and may include fatigue, headache, muscle aches and fever.

Blumberg emphasizes that the side effects are “not that bad,” especially when compared with the protection of being fully vaccinated. He said to remember that younger people are likely to have more adverse reactions to any immunization, not just the COVID-19 vaccines.

Some medical experts, including our nation’s leading infectious disease expert Anthony Fauci, have said side effects are just a sign that your immune system is reacting properly to the vaccine and building protection.  

“Whether you have side effects following vaccination or not, the vast majority of people are protected,” said Blumberg.

Additionally, Blumberg cited Phase 3 studies of the vaccines, which showed 95% protection against the disease.

For those who aren’t able to get their second dose on the exact given date, don’t worry. The CDC said doses can be given up to six weeks apart. If it’s longer, that’s OK too, said Blumberg. It’s truly better late than never, in this case.

“Even a month or two too late, we fully expect it to work just as well.” said Blumberg.

Even if you’re a couple months late, you won’t have to restart your vaccine series. Whatever you do, advised Blumberg, just get your second dose.

Learn how to schedule your COVID-19 vaccine.

When to contact your provider

If you're experiencing COVID-19 symptoms, contact your primary care provider. UC Davis Health patients can use the MyUCDavisHealth symptom tracker. Telehealth video visits are also available during regular business hours.

If you have a medical emergency, call 911 and notify them of your COVID-19 symptoms.

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