While COVID-19 vaccination problems have let thousands of San Diegans down between their first and second doses, local researchers say they should not worry about getting your second shot late.
What is more important is to come back for the next appointment as soon as it is available, says dr. Mark Sawyer, an infectious disease expert at Rady Children’s Hospital, who served on the Food and Drug Administration’s advisory panels on the safety and efficacy of Moderna, Pfizer and Vaccines Johnson & Johnson.
“People do not have to worry about losing their first dose if they have to wait five weeks or six weeks or seven weeks between dose one and dose two,” Sawyer said. “It will still work, and they will be protected.”
About 307,000 San Diegans who received a COVID-19 vaccine needed a second dose, according to the province’s dashboard, as it required two shots of the Moderna and Pfizer vaccinations to maximize immunity to the coronavirus. And while the Centers for Disease Control and Prevention recommends getting a second chance within the first six weeks after the first, it will not happen to some residents due to a severe shortage of vaccine from Massachusetts’ biotechnology Moderna.
During the week’s weekly coronavirus briefing, officials said the ongoing problems with the provision of vaccines have not yet been resolved. And while local COVID-19 numbers are heading in the right direction, with 352 coronavirus infections and 17 new hospitalizations reported on Wednesday, the recent progress will not be safe until the vast majority of San Diegans are vaccinated.
“It’s a battle. It is very difficult, “said Nathan Fletcher, the county’s supervisor. “I know it creates frustration.”
It also creates confusion for people wondering if they will have to start the whole vaccination process again due to a delayed second dose.
The short answer? No.
“If the second dose is administered outside these intervals, it is not necessary to restart the series,” reads CDC guidelines posted online in mid-February.
Waiting longer for your next dose can even be helpful, says Dr. Douglas Richman, a virologist at UC San Diego, notes that other multidose vaccines, such as measles, tetanus and hepatitis A, often divide shots by two to six months – sometimes longer.
“The delay does not worry me at all, and it can be beneficial,” Richman said. “The range of response for a boost improves the longer you wait.”
The recommended duration of the second dose for the Moderna and Pfizer vaccines – four and three weeks respectively – is based on the clinical trials. These trials are designed to quickly test whether the vaccines are safe and effective; longer gaps between doses would have delayed the responses.
It takes about two weeks to get a complete immune response to a vaccine, so three to four weeks is at the shorter end of when it makes sense to get a second dose. The reaction involves both antibodies – Y-shaped proteins that can cover a virus and prevent infection – and T cells, which can kill infected cells before they inject more virus.
Most of these immune cells will eventually die, but a few hold on if you are exposed to the same virus again. These so-called memory cells can take a month or longer to form, Richman says. Once they do, it returns a faster, stronger immune response than you had the first time. This is the point of getting a boost shot.
In this line, researchers reported that the coronavirus vaccine from British pharmaceutical giant AstraZeneca is 55 percent effective for people who received both doses in less than six weeks, but that efficacy increases at longer intervals, reaching 82 percent among participants. who waited at least 12 weeks. for their second hold.
And while you wait, there is enough data to show that the first dose provides strong short-term protection. According to data submitted to the FDA, a single ingestion of Moderna’s vaccine is approximately 80 percent effective in preventing people from becoming ill with COVID-19.
However, it is unclear how long single-dose protection lasts. And with increasing evidence that some coronavirus variants are not so effectively stopped by antibodies, it’s still important to get your second dose as soon as you can.
‘You strengthen your reaction (and) your antibodies after the second survey, so that you have a higher level. As your immune response wears off over time, you probably have more endurance, and you probably have more protection, ‘Richman said. “There are very good reasons to get a second chance, no question about it.”
Another good reason: the current COVID-19 vaccines are very effective in preventing serious illness and death. On Wednesday, the province reported 25 additional coronavirus-related deaths, bringing the region to 3,342.