First reported in late December 2019, the COVID-19 pandemic has been the cause of death for more than 539,000 Americans as of March 9, 2021. Fortunately, daily new cases dropped substantially from January to February 2021 following the Centers for Disease Control and Prevention (CDC) approval of two vaccines. With more than 93 million doses administered, a third vaccine was approved on February 27.

The first two vaccines approved in the US were developed by Moderna and Pfizer-BioNTech, both of which require two doses. The latest approved vaccine, from Johnson & Johnson, is the first single-shot vaccine, but it is only available via emergency use authorization (EUA). The following is a breakdown of the vaccine, its efficacy, and distribution plans.

Phase 3 ENSEMBLE Study

In testing the efficacy of its vaccine, Johnson & Johnson conducted a Phase 3 ENSEMBLE clinical trial, which involved 43,783 participants in eight countries, 44 percent of whom were from the US. Moreover, 41 percent of participants had comorbidities that suggest a higher risk of severe COVID-19 symptoms. The double-blind, placebo-controlled study included efficacy assessments at 14 and 28 days.

According to the CDC, the vaccine was 66.3 percent effective at protecting those with no prior evidence of infection against COVID-19. It was even more effective two weeks post-vaccination. Of those who registered a positive COVID-19 diagnosis after vaccination, none required hospitalization.

"We believe the Johnson & Johnson single-shot COVID-19 vaccine is a critical tool for fighting this global pandemic, particularly as it shows protection across countries with different variants," noted Johnson & Johnson chief scientific officer Paul Stoffels. "A vaccine that protects against COVID-19, especially against the most dire outcomes of hospitalization and death, will help ease the burden on people and the strain on health systems worldwide."

100 Million Vaccines to the US

The Johnson & Johnson vaccine received EUA on February 27, 2021, and shipping began immediately thereafter. An expected 20 million doses were slated for distribution throughout the US in March alone, with 100 million to be distributed within the first six months of 2021. Distribution will be managed by the US government.

Potential Side Effects

It's not uncommon for vaccines to have relatively minor side effects. Some that have been associated with the Johnson & Johnson vaccine include pain and swelling in the shot area as well as fever, nausea, muscle pain, and fatigue. Side effects typically appear within two days of receiving the vaccine and last no more than a few days. During trials, they were more common in people between the ages of 18 to 59.