Timeline of the COVID-19 pandemic in the United States (2021)

The timeline of the COVID-19 pandemic in the United States in 2021 details the events and developments related to the COVID-19 pandemic in the United States during the year 2021. This period was marked by the widespread distribution of vaccines, the emergence of new variants, and ongoing public health measures.

January 2021

COVID-19 cases in the United States

In January 2021, the United States continued to experience high numbers of COVID-19 cases and deaths. The Biden administration took office on January 20, 2021, and immediately implemented a national strategy to combat the pandemic. This included accelerating the distribution of vaccines and increasing testing and contact tracing efforts.

Vaccine Distribution

The vaccination campaign began to ramp up significantly. The Pfizer–BioNTech COVID-19 vaccine and Moderna COVID-19 vaccine were the primary vaccines being distributed. Efforts were made to prioritize healthcare workers, the elderly, and other high-risk groups.

February 2021

In February, the pace of vaccinations increased, with millions of doses being administered weekly. The Centers for Disease Control and Prevention (CDC) issued new guidelines for vaccinated individuals, allowing for some relaxation of restrictions.

Emergence of Variants

The Alpha variant (B.1.1.7), first identified in the United Kingdom, was detected in several states. This variant was more transmissible, leading to concerns about increased case numbers.

March 2021

COVID-19 deaths in the United States

By March, over 100 million vaccine doses had been administered. The Johnson & Johnson COVID-19 vaccine received emergency use authorization, providing a single-dose option to accelerate the vaccination process.

Public Health Measures

Despite the progress in vaccinations, public health officials urged continued adherence to mask mandates and social distancing, especially in light of the emerging variants.

April 2021

In April, the United States faced a temporary pause in the use of the Johnson & Johnson vaccine due to rare cases of blood clots. This pause was lifted after a thorough safety review.

Vaccine Eligibility

Vaccine eligibility expanded to include all adults aged 16 and older, marking a significant milestone in the vaccination campaign.

May 2021

In May, the CDC updated its guidance, stating that fully vaccinated individuals could resume activities without wearing masks or physically distancing, except where required by laws or regulations.

Vaccination Milestones

The United States reached the milestone of administering 200 million vaccine doses. Efforts continued to address vaccine hesitancy and ensure equitable distribution.

June 2021

The pace of vaccinations began to slow in June, with a focus on reaching unvaccinated populations. The Delta variant (B.1.617.2), first identified in India, began to spread rapidly, raising concerns about potential surges in cases.

July 2021

In July, the Delta variant became the dominant strain in the United States. This led to a rise in cases, particularly in areas with low vaccination rates.

Public Health Response

The CDC recommended that even fully vaccinated individuals wear masks indoors in areas of substantial or high transmission.

August 2021

In August, the FDA granted full approval to the Pfizer-BioNTech vaccine for individuals aged 16 and older, a move expected to boost vaccination rates.

September 2021

The Biden administration announced plans for booster shots to enhance protection against the Delta variant, pending regulatory approval.

October 2021

By October, booster shots were being administered to eligible populations, including the elderly and those with underlying health conditions.

November 2021

In November, the CDC expanded booster shot eligibility to all adults, as the holiday season approached and concerns about indoor gatherings increased.

December 2021

The year ended with the emergence of the Omicron variant, leading to renewed concerns about the pandemic's trajectory and the effectiveness of existing vaccines.

Related pages

• COVID-19 pandemic in the United States
• COVID-19 vaccination in the United States
• SARS-CoV-2 variants