Coronavirus disease (COVID-19): Vaccines

Is there a vaccine for COVID-19? 

Yes, there are now several vaccines that are in use. The first mass vaccination program started in early December 2020 and as of and as of 15 February 2021, 175.3 million vaccine doses have been administered. At least 7 different vaccines (3 platforms) have been administered.

WHO issued an Emergency Use Listing (EULs) for the Pfizer COVID-19 vaccine (BNT162b2) on 31 December 2020. On 15 February 2021, WHO issued EULs for two versions of the AstraZeneca/Oxford COVID-19 vaccine, manufactured by the Serum Institute of India and SKBio. On 12 March 2021, WHO issued a EUL for the COVID-19 vaccine Ad26.COV2.S, developed by Janssen (Johnson & Johnson). WHO is on track to EUL other vaccine products through June. 

The products and progress in regulatory review by WHO is provided by WHO and updated regularly. 

Once vaccines are demonstrated to be safe and efficacious, they must be authorized by national regulators, manufactured to exacting standards, and distributed. WHO is working with partners around the world to help coordinate key steps in this process, including facilitating equitable access to safe and effective COVID-19 vaccines for the billions of people who will need them. 

Will COVID-19 vaccines provide long-term protection?

Because COVID vaccines have only been developed in the past months, it’s too early to know the duration of protection of COVID-19 vaccines. Research is ongoing to answer this question. However, it’s encouraging that available data suggest that most people who recover from COVID-19 develop an immune response that provides at least some period of protection against reinfection – although we’re still learning how strong this protection is, and how long it lasts.

How quickly could COVID-19 vaccines stop the pandemic?

The impact of COVID-19 vaccines on the pandemic will depend on several factors. These include the effectiveness of the vaccines; how quickly they are approved, manufactured, and delivered; the possible development of other variants, and how many people get vaccinated. 

Whilst trials have shown several COVID-19 vaccines to have high levels of efficacy, like all other vaccines, COVID-19 vaccines will not be 100% effective. WHO is working to help ensure that approved vaccines are as effective as possible, so they can have the greatest impact on the pandemic.

What types of COVID-19 vaccines are being developed? How would they work?

Scientists around the world are developing many potential vaccines for COVID-19. These vaccines are all designed to teach the body’s immune system to safely recognize and block the virus that causes COVID-19.

Several different types of potential vaccines for COVID-19 are in development, including:

• Inactivated or weakened virus vaccines, which use a form of the virus that has been inactivated or weakened so it doesn’t cause disease, but still generates an immune response.
• Protein-based vaccines, which use harmless fragments of proteins or protein shells that mimic the COVID-19 virus to safely generate an immune response.
• Viral vector vaccines, which use a safe virus that cannot cause disease but serves as a platform to produce coronavirus proteins to generate an immune response.
• RNA and DNA vaccines, a cutting-edge approach that uses genetically engineered RNA or DNA to generate a protein that itself safely prompts an immune response.

Will other vaccines help protect me from COVID-19?

Currently, there is no evidence that any other vaccines, apart from those specifically designed for the SARS-Cov-2 virus,  will protect against COVID-19.

However, scientists are studying whether some existing vaccines – such as the Bacille Calmette-Guérin (BCG) vaccine, which is used to prevent tuberculosis – are also effective for COVID-19. WHO will evaluate evidence from these studies when available.

What are the benefits of getting vaccinated?

The COVID-19 vaccines produce protection against the disease, as a result of developing an immune response to the SARS-Cov-2 virus.  Developing immunity through vaccination means there is a reduced risk of developing the illness and its consequences. This immunity helps you fight the virus if exposed. Getting vaccinated may also protect people around you because if you are protected from getting infected and from disease, you are less likely to infect someone else. This is particularly important to protect people at increased risk for severe illness from COVID-19, such as healthcare providers, older or elderly adults, and people with other medical conditions.

Who should get the COVID-19 vaccines?

The COVID-19 vaccines are safe for most people 18 years and older, including those with pre-existing conditions of any kind, including auto-immune disorders. These conditions include hypertension, diabetes, asthma, pulmonary, liver, and kidney disease, as well as chronic infections that are stable and controlled. 

If supplies are limited in your area, discuss your situation with your care provider if you:

• Have a compromised immune system
• Are pregnant or nursing your baby
• Have a history of severe allergies, particularly to a vaccine (or any of the ingredients in the vaccine)
• Are severely frail 

Can we stop taking precautions after being vaccinated?

Vaccination protects you from getting seriously ill and dying from COVID-19. For the first fourteen days after getting a vaccination, you do not have significant levels of protection, then it increases gradually. For a single-dose vaccine, immunity will generally occur two weeks after vaccination. For two-dose vaccines, both doses are needed to achieve are required to provide the highest level of best immunity possible. 

While a COVID-19 vaccine will protect you from serious illness and death, we still don’t know the extent to which it keeps you from being infected and passing the virus on to others. To help keep others safe, continue to maintain at least a 1-meter distance from others, cover a cough or sneeze in your elbow, clean your hands frequently and wear a mask, particularly in enclosed, crowded, or poorly ventilated spaces. Always follow guidance from local authorities based on the situation and risk where you live.

Can I have the second dose with a different vaccine than the first dose?

Clinical trials in some countries are looking at whether you can have the first dose from one vaccine and a second dose from a different vaccine. There isn't enough data yet to recommend this type of combination. 

Can the COVID-19 vaccine cause a positive test result for the disease, such as for a PCR or antigen test?

No, the COVID-19 vaccine will not cause a positive test result for a COVID-19 PCR or antigen laboratory test. This is because the tests check for active disease and not whether an individual is immune or not. However, because the COVID-19 vaccine prompts an immune response, it may be possible to test positive in an antibody (serology) test that measures COVID-19 immunity in an individual.

Should I be vaccinated if I have had COVID-19?

Even if you have already had COVID-19, you should be vaccinated when it is offered to you. The protection that someone gains from having COVID-19 will vary from person to person, and we also don’t know how long natural immunity might last. 

Is the vaccine safe for children?

Vaccines are usually tested in adults first, to avoid exposing children who are still developing and growing. COVID-19 has also been a more serious and dangerous disease among older populations. Now that the vaccines have been determined to be safe for adults, they are being studied in children. Once those studies have been completed, we should know more and guidelines will be developed.

In the meantime, make sure children continue to physically distance themselves from others, clean their hands frequently, sneeze and cough into their elbow and wear a mask if age-appropriate.

Do the vaccines protect against variants?

The COVID-19 vaccines are expected to provide at least some protection against new virus variants and are effective at preventing serious illness and death. That’s because these vaccines create a broad immune response, and any virus changes or mutations should not make vaccines completely ineffective. If any of these vaccines become less effective against one or more variants, it will be possible to change the composition of the vaccines to protect against these variants. Data continues to be collected and analyzed on new variants of the COVID-19 virus. 

While we are learning more, we need to do everything possible to stop the spread of the virus in order to prevent mutations that may reduce the efficacy of existing vaccines. This means staying at least 1 meter away from others, covering a cough or sneeze in your elbow, frequently cleaning your hands, wearing a mask, and avoiding poorly ventilated rooms or opening a window. 

How will we know if COVID-19 vaccines are safe?

Ensuring the safety and quality of vaccines is one of WHO’s highest priorities. WHO works closely with national authorities to ensure that global norms and standards are developed and implemented to assess the quality, safety, and efficacy of vaccines. 

The process to develop COVID vaccines is fast-tracked while maintaining the highest standards: Given the urgent need to stop the pandemic, pauses between steps, often needed to secure funding, have been shortened, or eliminated, and in some cases, steps are being carried out in parallel to accelerate the process, wherever that is safe to do. COVID-19 vaccine developers have issued a joint pledge not to seek government approval for their vaccines until they’ve been proven to be safe and effective. 

There are many strict protections in place to help ensure that COVID-19 vaccines are safe. Like all vaccines, COVID-19 vaccines are going through a rigorous, multi-stage testing process, including large (phase III) trials that involve tens of thousands of people. These trials, which include some groups at high risk for COVID-19 (certain groups like pregnant and lactating women were not included in vaccine trials), are specifically designed to identify any common side effects or other safety concerns.

Once a clinical trial shows that a COVID-19 vaccine is safe and effective, a series of independent reviews of the efficacy and safety evidence is required, including regulatory review and approval in the country where the vaccine is manufactured, before WHO considers a vaccine product for EUL or prequalification. EUL or Prequalification verifies to those countries that would want to procure a particular vaccine that there has been an assurance by WHO that the regulatory review process, usually in the country of manufacture, has held up to the highest standards. Part of this process also involves a review of all the safety evidence by the Global Advisory Committee on Vaccine Safety.

An external panel of experts convened by WHO analyzes the results from clinical trials, along with evidence on the disease, age groups affected, risk factors for disease, and other information.  The panel recommends whether and how the vaccines should be used. Officials in individual countries decide whether to approve the vaccines for national use and develop policies for how to use the vaccines in their country based on the WHO recommendations.

After a COVID-19 vaccine is introduced, WHO supports work with vaccine manufacturers, health officials in each country, and other partners to monitor for any safety concerns on an ongoing basis.

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