According to preliminary data from the US Center for Disease Control and Prevention, most people who received the first dose of the Kovid-19 vaccine are receiving their second dose on time.
But CDC researchers warn that early groups preferred to receive the vaccine – health care workers and long-term care facility residents – have easier access to a second dose through their workplace or residence.
“As priority groups broaden, adherence to recommended dosage intervals may decrease,” the researchers wrote in their report published on Monday.
For Pfizer / BioNotech and Modern Vaccines, a second dose is recommended after 21 and 28 days, respectively, but researchers have stated in their report that up to 42 days between doses are allowed, if needed.
The report includes data from more than 37 million people who received at least their first dose of the Kovid-19 vaccine between 14 December and 14 February.
The researchers analyzed the data when a first dose was received, a second dose was received, and whether that second dose was received on time. The data came from 58 courts across the United States.
Researchers found that among those who had gone enough time to receive a second dose, 88% had completed their second dose, 8.6% had not, but still enough time to receive their second dose. And 3.4% missed were completely the second dose – mean at least 42 days after their first dose was found.
In the data, among those who received both doses, the researchers found that 95.6% received their second dose within the recommended time interval.
Researchers noted that several winter weather events led to delivery challenges and vaccination clinics canceling appointments during the study, and more research is needed to examine the completion of second doses over the long term.
“Continuous monitoring of jurisdiction and chain characteristics is important to ensure equity in vaccination administration and vaccination coverage, particularly as vaccination efforts extend to additional population groups,” the researchers wrote.