- Experts say you shouldn’t worry too much if your second dose of the COVID-19 vaccine is postponed for a few days or even a few weeks.
- Nonetheless, they recommend you make certain your follow-up dose is completed within 6 weeks of the first shot.
- They say second doses are more important now due to the emergence of COVID-19 variants.
- They add that the new single-dose Johnson & Johnson vaccine makes things easier.
Supply shortages could mean those waiting for a second dose of the COVID-19 vaccine may have to keep waiting, but experts say there’s no need to panic.
Both the Pfizer and Moderna vaccines are given in a two-dose series with a 21-day interval between doses for the Pfizer vaccine and a 28-day interval between doses for the Moderna vaccine.
Experts say those waiting for their second shot shouldn’t worry if it is delayed.
“If your dose is delayed for a few days or a few weeks, I would not be concerned about that,” Dr. Dean Blumberg, chief of pediatric infectious diseases at the University of California Davis, told Healthline.
“Ideally, people would get the vaccine on time, but if it is delayed, you don’t have to restart the vaccine series. We do know that one dose of vaccine results in about 90 percent protection in terms of the Pfizer-BioNTech and Moderna vaccines. That begins about 2 weeks following the first immunization,” Blumberg said.
According to data from the Centers for Disease Control and Prevention (CDC), more than 60 million people in the United States have received at least one dose of the COVID-19 vaccine. Of them, more than 31 million have been given two doses.
Dr. Grace Lee, an infectious disease specialist at Stanford University in California, says part of the concern in delays of the second dose is a weakening immune response from only one shot.
“We don’t have any information about the durability of that immune response. If you haven’t had an infection with the new coronavirus, the first dose is considered your priming dose. Typically, the boost ensures your immune response would be durable over time. So, if you only get one dose, the concern I would have personally is whether or not there would be waning,” she told Healthline.
Whether it’s more important for more people to have had the first shot or completed the whole series with both shots is complex.
“It’s very complicated. On the one hand, modeling suggests the first dose is more important than the second dose, and that getting that first dose into people will have more of a population impact. Yet, we also know that when we have these priority groups, it’s very important to prioritize those who are most at risk, such as older individuals as well as essential and healthcare workers,” Blumberg said.
“I think there needs to be a combination distribution to make sure those older individuals are fully protected as well as healthcare workers and essential workers,” he added.
“If it is not feasible to adhere to the recommended interval and a delay in vaccination is unavoidable, the second dose of Pfizer/BioNTech and Moderna COVID-19 vaccines may be administered up to 6 weeks (42 days) after the first dose,” the CDC states.
Currently, there is limited information on how effective the COVID-19 vaccine is if the second dose is given outside a 6-week window.
“What the CDC has said has been ‘don’t let doses sit on the shelves,’” Lee said. “Meaning don’t hold doses trying to make sure that everyone gets a second dose on day 21 or day 28. Make sure that you’re giving whatever doses you have under the assumption that the supply chain will come in and by the time the individuals are ready to get their second dose, there will be additional supply available. I think this is the right principle.”
Source: healthline