The authorized or approved vaccines were initially tested in animals and early phase clinical trials, in which scientists evaluated different doses, checked for the expected immune responses and monitored for potential safety issues. To find out whether the shots prevent disease and are safe, the vaccines that passed the first set of tests were then evaluated in phase 3 trials.
The Moderna and Novavax phase 3 trials each included about 30,000 volunteers,
Misconception: COVID-19 Misconceptions
Pace of U.S. Vaccinations vs. the World
President Joe Biden boasts that the U.S. is on pace to be the first country in the world to vaccinate 100 million people. That’s true, but per capita the U.S. is not tops in the world in vaccinations.
The Evolving Science of Face Masks and COVID-19
Since the Centers for Disease Control and Prevention began recommending that members of the public mask up last spring, additional research has backed the use of face masks to combat the coronavirus, but knowledge gaps still remain. Here, we summarize the evidence.
A Guide to Johnson & Johnson’s COVID-19 Vaccine
The Johnson & Johnson vaccine is the third COVID-19 vaccine to be authorized by the Food and Drug Administration. Here, we give a rundown of basic facts about the vaccine and an overview of how it works.
No Evidence Vaccines Impact Fertility
Q: Do the COVID-19 vaccines cause infertility?
A: There’s no evidence that approved vaccines cause fertility loss. Although clinical trials did not study the issue, loss of fertility has not been reported among thousands of trial participants nor confirmed as an adverse event among millions who have been vaccinated.
Biden Hasn’t Reduced COVID-19 Testing at the Border
The Biden administration has made no changes to COVID-19 testing policies for either U.S. Immigration and Customs Enforcement or Customs and Border Patrol. But a claim circulating online falsely suggests that the administration has stopped testing detained immigrants before they are released.
How lethal is COVID-19?
It’s difficult to know exactly how deadly COVID-19 is, but as the World Health Organization has written, studies estimate that the infection fatality ratio, or percentage of deaths out of all infections, is between 0.5% and 1%. The true rate isn’t clear, since the pandemic is ongoing and not all infections have been diagnosed.
The observed case fatality rate, or percentage of deaths out of confirmed cases, was 1.2% in the United States as of April 6,
How long will a person be protected if vaccinated against COVID-19?
It’s not known exactly how long vaccination lasts, particularly against the omicron variant. But studies of previous variants have suggested that COVID-19 vaccination protects against infection or mild disease for several months, while protection against more serious illness is longer-lasting, on the order of six months or more.
A systematic review of studies conducted prior to omicron, for example, found that for the four main COVID-19 vaccines used worldwide,
How does community immunity apply to COVID-19?
Community immunity, often referred to as herd immunity, refers to a situation in which enough of a population is immune to an infectious disease, either through vaccination or prior infection, to largely stop transmission of the disease and indirectly protect those who aren’t immune. The more contagious the disease, the higher proportion of people need to have immunity to get community immunity.
This classical definition applies to diseases such as measles,
Could a COVID-19 vaccine become mandatory?
Some employers have required their employees to be vaccinated, or undergo regular testing, for COVID-19. The U.S. Equal Employment Opportunity Commission has said that employers aren’t prevented from having a mandatory vaccination policy for COVID-19 for employees who are physically in the workplace, as long as employers comply with federal laws stipulating that reasonable accommodations should be made for workers who cannot be immunized because of a disability or religious reason.
President Joe Biden also signed executive orders in September 2021 to require all federal workers and contractors who do business with the federal government to be vaccinated.