It is safe to administer COVID-19 vaccines the same day as other vaccines, according to the U.S. CDC's changed guidance that previously suggested people wait two weeks after their final COVID-19 vaccine before getting any other shots.

The reason for the earlier policy was "[O]ut of an abundance of caution and not due to any known safety or immunogenicity concerns." (Immunogenicity measures how well a vaccine can cause an immune response against a virus or other pathogen).

Now that scientists have collected and analyzed more data the organization has changed its stance, but recommends that health care providers administer different vaccines in different injection sites. If a person gets a COVID-19 shot in their upper left arm for example, they should get any other vaccine in their right upper left arm, or at least one inch away from the COVID-19 injection site.

Vaccines that are likely to cause a local reaction like soreness, rashes, or itching should be given in different limbs, according to reccomendations. COVID-19 vaccines fall into this category, and so do the bacille Calmette-Guérin tuberculosis (BCG) and Pertussis vaccines.

At this time, we don't know whether COVID-19 vaccine side effects will be worse when they're given at the same time as other vaccines, especially ones with live virus or adjuvants (vaccine ingredients that help enhance the body's immune response to a virus or pathogen). Regions or locations using COVID-19 vaccines that may contain live virus may or may not choose not to follow this guidance until more data is evaluated.

To be sure, some national health authorities around the world still recommend spacing out the COVID-19 vaccine and other shots. In the UK, for example, guidance is still to keep a 7 day gap where possible. It should also be noted that no vaccines used in the United States contain live virus, so US guidance may be best suited for specific areas where no live virus COVID-19 vaccines are given, including in Zimbabwe.