Missing doses, especially for multi-shot vaccines, aren't uncommon. The consequence of missing out on the second dose of covid vaccine is that you are not protected-you get exposed to the infection, you may get infected, get the disease, and even get it severely.”
Single-dose does not induce strong immunity. The novel Coronavirus vaccine is a non-infectious, non-replicating vaccine. Unlike a live virus vaccine which multiplies in the body to give you immunity, the non-replicating vaccine works only to prime the immune system, and gradually gets degraded by the body’s physiology.
One dose of live virus vaccine is more closely mimicking the original infection whereas one dose of the non-replicating vaccine is only priming the system. That is the reason we need to boost it through a second dose. Even if we increase the potency of the first dose, we may have an increase in efficacy. But it will still be a priming dose only.
What to do in case of a missed dose?
If a situation that's out of your control arises and causes you to miss your second dose, don't panic.
"It's best to get your second dose as close to the recommended interval as possible. But, if a delay is unavoidable, missing this window doesn't mean you've missed your only chance of getting your second dose. It also doesn't mean you need to start your vaccination plan over completely," says Dr. Ashley Drews, medical director of infection prevention and control at Houston Methodist.
While the first and second doses for Covaxin need to be taken 28 days apart, the Indian government recommends that Covishield’s second dose be taken 12 weeks after the first.
Even if the recommended time period has lapsed, it is advisable for a person to get their second dose, opines Dr. KP Aravindan, who is in the expert panel of COVID-19 for the state government. “There is no need of undue concern now since it has been understood that the second dose of Covishield can be taken within eight to 12 weeks of the first. However, not getting the second dose within this period is not a harmful thing. It may affect the effectiveness a little but that is still not clear. We don’t have the data to say it clearly now,” he says.
Yes, it is true the even if your second dose is significantly delayed, you do not need to start the vaccine series all over but it may, of course, impact the effectiveness of the vaccine. Therefore it's important to take steps to help ensure you get your second dose on schedule.