Infectious Diseases Data Verified

What if Your Second Dose of the COVID-19 Vaccine Is Delayed?

Published on May 12, 2021 and last reviewed on Jan 25, 2023   -  4 min read


COVID-19 vaccines scientifically reduce morbidity and mortality rates in COVID-19 patients. Read the article below to know more.

What if Your Second Dose of the COVID-19 Vaccine Is Delayed?

What if the Second Dose of the COVID-19 Vaccine Is Delayed?

Researchers say that do not panic if the second dose of the COVID-19 vaccine is delayed for a few weeks or a few days. But they recommend always having a follow-up on the second dose, and getting vaccinated within six weeks of the first dose is important. It is because the second dose is more important for broader protection against the COVID-19 variants. They also added that the single-dose Johnson and Johnson vaccine is making things easier. However, there were situations where supply shortages of vaccines occurred, and those people who were waiting for the second dose of vaccine had to wait until the vaccine arrived.

What Is the Importance of the Second Shot of the COVID-19 Vaccine?

The first dose is considered the prime dose, and the second dose makes our immune response more durable over time. Many infectious disease specialists say that a weakening immune response from only one shot is noticed if there is a delay in the second shot of the COVID-19 vaccine. Still, the durability of that immune response is unknown. Experts say that the protective shield against COVID-19 disease will vanish over time when we take only one dose. So, people need to complete the whole series of both shots.

In addition, follow the right principle by not holding doses to ensure everyone gets a second dose at that particular interval.

Initially, scientists suggested that vaccines should be given first to the people who are at risk or the priority groups, such as:

  • Older individuals.

  • Healthcare professionals.

  • Essential workers.

What Could Be the Reasons for Missing the Second Dose of the COVID-19 Vaccine?

The following are some of the reasons for missing the second dose of the COVID-19 vaccine. They are,

1. Getting COVID-19 After the First Dose:

If a person had COVID-19 shortly after or just before the first dose, he should recover before getting the second dose. The vaccine starts producing antibodies after seven days of the first shot, and a person should not get the second shot if he still have COVID-19 symptoms. He should be in isolation if he has COVID-19 symptoms and should not come in contact with anyone at the vaccination site. Get the second shot within six weeks between the doses, and should inform about the current medical condition before a person gets vaccinated.

2. If Undergone Specific Treatments:

A person could have received monoclonal antibody therapy while ill. He should wait for 90 days before the second dose, or maybe have got convalescent plasma during a COVID-19 attack and should wait for at least three months before the second dose.

3. Bodily Reaction After Getting Vaccinated:

Some people are worried about the side effects worsening after receiving the second dose. Side effects after the first and second doses are common, which include-

  • Pain at the injection site.

  • Fatigue.

  • Fever.

  • Headache.

  • Muscle ache.

The fever is common after the second dose, and symptoms last for a couple of days. If a person is an immediate allergic reactive person or have anaphylaxis, they need to evaluate with an allergist before getting the second shot.

4. Canceled Appointments:

If second dose appointments are canceled, people find it hard to reschedule with the second dose.

5. Personal Crisis:

Maybe personal reasons could have made a person miss the second dose of the COVID-19 vaccine. For example, in case a person is moving back to the area of workplace or moved to his own locality after the first dose.

6. Misperception About the Second Dose:

Many people are confused or wrongly think that one shot of the vaccine is enough. But on getting both doses of vaccine, maximum antibodies are produced to protect us against the novel coronavirus. The second dose provides us wider protection from being hospitalized and becoming seriously ill. For example, studies show-

Pfizer Vaccine:

  • First dose: 52 % effectiveness.

  • Second dose: 95 % effectiveness.

Moderna Vaccine:

  • First dose: 80 % effectiveness.

  • Second dose: 94.1 % effectiveness.

So if a person is not receiving both doses, he will not be as protected from becoming seriously ill with COVID-19.

7. Limited Stock of the Second Dose:

If there is a limited supply of the second dose, we are more likely to miss our second COVID-19 vaccine.

What Should a Person Know if They Miss Second COVID-19 Vaccine Dose?

Do Not Panic:

Do not miss out on the second dose, but if the situation is out of control and causes someone to miss the second dose, do not panic.

Do Not Start Again With a New Vaccination Series:

Make sure that a person gets the second dose as close to the recommended interval, but an unavoidable delay does not mean that a person missed the only chance of getting the second dose, or it does not mean that a person should start the vaccination schedule again.

Contact the Vaccine Distributor:

If a person missed their second dose, they should only get the second dose to complete the vaccination series. A person can contact the vaccination distributor to reschedule the second dose as soon as possible.


The COVID-19 vaccines save thousands of lives and are our best way of ending this pandemic. Although, some rare cases cannot get vaccinated for a specific health reason like severe allergic reactions. The sincere advice is that everyone eligible should get vaccinated as soon as the vaccine is available to them and not delay the second dose if a person gets a two-dose vaccine. Also, if a person gets vaccinated, and follow the COVID-19 safety precautions like wearing masks, social distancing, frequently washing hands, avoiding frequent outings, and not touching the face frequently.


Last reviewed at:
25 Jan 2023  -  4 min read




Comprehensive Medical Second Opinion.Submit your Case

Related Questions & Answers

Frequently Asked Questions About COVID-19 Vaccines

Article Overview: COVID-19 vaccines can be a real lifesaver. Read this to know the answers to the common questions and doubts on COVID-19 vaccines. Read Article

Sugreev Singh
Sugreev Singh
Internal Medicine

1. Which Vaccine Is Licensed for COVID-19 Worldwide? In India earlier, Covaxin, Covishield, Sputnik V, Johnson & Johnson, and ZyKoV-D were authorized by the Central Drugs Standard Control Organization. Currently, there are 38 approved vaccines (that are approved by different national government ...  Read Article

Myths and Facts About COVID-19 Vaccines

Article Overview: There are lots of misconceptions and facts about the COVID-19 vaccines. This article will help to understand and clear the misconceptions about vaccines. Read Article

Raveendran S. R
Raveendran S. R

Myths About COVID-19 Vaccines: 1) Myth: COVID-19 vaccines were developed rapidly, so they are not reliable. Fact: COVID-19 vaccines, or any other vaccine for that purpose, undergoes extensive testing before getting approved. They undergo various clinical trials to meet safety standards. The clinical...  Read Article

COVID-19 and Other Seasonal Co-Infections

Article Overview: This article discusses the onset of disease, symptoms, complications, and warning signs to differentiate COVID-19 from various other seasonal co-infections. Read Article

Ajmera Jail Singh
Ajmera Jail Singh
General Practitioner

Introductions: COVID-19 and its variants has affected almost all the countries in the world. With the symptoms of COVID-19 not very specific and the prevalence of other seasonal infections every year, it is becoming a challenge to diagnose patients who present with influenza-like illnesses (ILI). Di...  Read Article

Popular Articles Most Popular Articles

Do you have a question on Covid-19 or Covid-19 Vaccine?

Ask a Doctor Online

* guaranteed answer within 4 hours.

Disclaimer: No content published on this website is intended to be a substitute for professional medical diagnosis, advice or treatment by a trained physician. Seek advice from your physician or other qualified healthcare providers with questions you may have regarding your symptoms and medical condition for a complete medical diagnosis. Do not delay or disregard seeking professional medical advice because of something you have read on this website. Read our Editorial Process to know how we create content for health articles and queries.