The Real Reason Some Moderna Vaccines Were Paused In California

While millions of people await their turn to receive the COVID-19 vaccine, many Californians found themselves disappointed as Moderna halted their distribution of one lot. According to Healthline, six people in the San Diego area suffered extreme allergic reactions post-vaccine. This was serious enough that health officials asked a pause to be placed on Lot 041L20A, the same lot the six reactions came from. There have already been over 330,000 vaccines given from this lot of 1,272,200, but six serious reactions is enough to investigate further.

In a Sacramento press release on January 17th, epidemiologist Dr. Erica S. Pan stated, "A higher-than-usual number of possible allergic reactions were reported with a specific lot of Moderna vaccine administered at one community vaccination clinic." Dr. Pan also stated to err on the side of caution and safety, there will be an investigation conducted by Moderna, the CDC, FDA, and the state, with updates provided regarding their findings.

While it may seem concerning, the Center for Disease Control states that a severe allergic reaction is rare in the Pfizer and Moderna COVID-19 vaccines, occurring in one out of 100,000 people. On January 20th, Moderna released a statement that after thorough discussions and evidence examination, distribution can resume using Lot 041L20A. In the press release (via KCRA3), Dr. Pan states they "found no scientific basis to continue the pause."

Is it possible that only one batch of vaccines could cause allergic reactions? Infectious disease physician Anne Liu says there is a possibility, although not likely, that the lot in question could have some abnormalities, as Moderna outsources manufacturing — or it could be completely coincidental. Dr. Liu also stated that pausing the vaccine distribution of the lot was the right choice, allowing time for investigating to get the necessary answers. Fortunately for California, there was not a long delay in hashing out any discrepancies and considering the lot safe for distribution, as the pause on distribution has now been lifted.