Is the COVID-19 Vaccine Effective Against the Delta Variant?

Alexis Bryan
Alexis Bryan23 Apr 2024
Reviewed and Fact Checked ✔️

More infectious strains of the coronavirus, such as the Delta variant, threaten protection from the currently approved vaccines. At this time, currently authorized vaccines are working. COVID-19 vaccination prevents severe illness, hospitalization, and death from the SARS-CoV-2 virus, but breakthrough cases are expected. 

Especially with the Delta variant circulating, breakthrough cases are expected. The best way to protect yourself against serious illness is still through vaccination. If you live or work in a substantial or high transmission area, getting vaccinated is even more important. Our team at Mira can help you find an appointment today.

What We Know about COVID-19 Vaccine Breakthrough Cases

COVID-19 vaccine breakthrough cases refer to those who are fully vaccinated yet test positive for COVID-19 cases. Those who are immunocompromised or over 65 years old are most at risk for breakthrough cases. 

Recently we have seen an increase in positive COVID-19 tests among those who have been fully vaccinated. The CDC is monitoring the situation to provide the best guidance on booster shots and public health protocols. COVID-19 vaccine breakthrough cases occur for two reasons:

  1. Increased infectiousness of variants
  2. Waning immunity from vaccination

The CDC has summarized the most important things to know about COVID-19 Vaccine Breakthrough Cases:

  • Breakthrough infections are expected. COVID-19 vaccines are effective at preventing most infections. However, like most vaccines, they are not 100% effective.
  • Fully vaccinated people with a breakthrough infection are less likely to develop serious illness than those who are unvaccinated and get COVID-19.
  • Even when fully vaccinated people develop symptoms, they tend to be less severe symptoms than unvaccinated people. This means they are much less likely to be hospitalized or die than people who are not vaccinated.
  • People who get vaccine breakthrough infections can be contagious.

COVID-19 Vaccine Breakthrough Case Infectiousness

A new study from the Netherlands was released last week suggesting that fully vaccinated people breakthrough cases are less infectious than COVID-19 cases among unvaccinated people. 68.6% of breakthrough infections tested positive compared with 84.9% of infections in unvaccinated patients. While vaccinated people can still become infected with COVID-19, they shed less virus, meaning they may be less likely to spread the virus.

COVID-19 Testing for Fully Vaccinated Individuals

To start, fully vaccinated means you have received both doses of an mRNA vaccine (which take two weeks to take full effect) or one dose of another approved vaccine. If you have been exposed to COVID-19, you should get tested 3-5 days after exposure whether or not you have symptoms. You should also get tested if you experience any flu-like symptoms to ensure it is not COVID-19. If possible, a PCR test is always recommended.

Getting tested even when you are vaccinated is important since you can still spread the virus. Given there is evidence that immunity from vaccination wanes, you never know who is vulnerable to infection around you. Especially since kids under 12 cannot yet get vaccinated, it is important to protect those around you.

COVID-19 Symptoms for Fully Vaccinated Individuals

COVID-19 vaccine breakthrough cases most often resemble a cold and can be resolved at home. Fully vaccinated individuals are extremely likely to have an asymptomatic infection after testing positive. If you do experience symptoms, it is very rare they will be serious enough to need hospitalization.

Health Image

Get affordable doctor copay without paying insurance premiums

Join 39,000 people and get Mira, the best alternative to traditional insurance. Enroll and use immediately. Plans start at only $45/mo.

Alexis Bryan

Alexis Bryan MPH, is a recent graduate of Columbia’s Mailman School of Public Health. She is passionate about increasing access to care to improve health outcomes. Outside of work, she loves to travel, read, and pay too much attention to her plants.

Get Health BenefitsGet Lab TestsTalk Therapy
Get ObamaCare
> See Plans