Several individuals have now been vaccinated against the novel coronavirus (COVID-19). And now, all of the recipients are lined up to have their second vaccination injection.

Concerns Rise After COVID Vaccine Causes Severe Side Effects in Some
(Photo : REUTERS/Oren Ben Hakoon)

While almost all believe that to get the highest level and longest-lasting defense, they need a second chance. How soon after the first one is the issue. And what happens if the next dose isn't given to a person? Here's what the specialists might say.

First Shot Reveals Promising Results

A number of recent data show that the first dose of the vaccine gives reasonably decent safety.

On Monday, the British government published figures showing that after one injection, the Pfizer-BioNTech vaccine was 72 percent effective against infection. It decreased by 75 percent the risk of hospitalization and death. A shot reduces the chance of death by more than half for people older than 80.

The research follows an Israeli analysis that reported similar findings for the Pfizer-BioNTech vaccine, released last Thursday.

The British government, which agreed to delay second shots for up to 12 weeks after a new, extremely infectious strain drove up cases of COVID-19 late last year, is welcome news.

How Long Will the First Dose Last?

However, one major question is how long safety from one dosage lasts.

"Although the numbers [from] a single dose do look interesting, the one thing we don't know is how durable it is," chief U.S. infectious disease expert Anthony Fauci said in a briefing last Feb. 19.

Since the virus is so recent and the vaccinations are much newer, there simply isn't any evidence for scientists to continue.

Yet other experts believe, based on what they have heard from other vaccinations, they know plenty.

What Side Effects Should I Get From COVID-19 Vaccine?

According to, NBC News medical contributor Dr. Kavita Patel said the side effects include localized reactions. According to Patel, these involve swelling, rash, or soreness at the injection site that has been reported in around 84 percent of recipients.

About 63 percent of individuals have reported having any exhaustion. Few individuals can also develop chills, fever or headache at the Centers for Disease Control and Prevention (CDC) and recommend that individuals who may not feel better after about 24 hours reach their doctor.

According to the WJLA article, the side effects could last up to three days and are much different from an allergic reaction. That's why patients are asked to stay around after the injection for 15-30 minutes to ensure no adverse reaction. It's rare, but there could be a possibly life-threatening response called anaphylaxis.

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What Happens if I Delay My Second COVID-19 Vaccine Shot?

According to Forbes, Pfizer CEO Albert Bourla said that there was no conclusive evidence yet as to whether it would be possible to exclude or delay the second dose of the coronavirus vaccine.

"We don't know what would happen if we didn't administer the second dose," Bourla told CNN White House correspondent Kaitlan Collins as quoted by Forbes.

On Thursday, research in Israel found that a single shot of the Pfizer-BioNTech vaccine was 85% effective against symptomatic COVID-19 within 15 to 28 days following the vaccine administration.

The requests for further comment were not received by Pfizer and BioNTech.

For the 95 percent effectiveness rate seen in clinical trials, Pfizer and BioNTech now prescribe two doses of the vaccine, given 21 days apart. But the study, undertaken by the Sheba Medical Center operated by the Israeli government and published in the medical journal The Lancet, could fuel disputes over whether governments should withhold a second dose in order to provide more people with a small supply of vaccines.

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