COVID-19: What we know about the future of COVID-19 vaccines

Today marks the start of the World Immunization Week. The COVID-19 pandemic, while draws the world’s attention to the vaccine, also reminds us of the importance of immunization, which saves millions of lives each year.

WHO is working with partners all over the world to accelerate research and development of a safe and effective vaccine and ensure equitable access for the billions of people who will need it. But even with an expedited process, development of a vaccine for COVID-19 will take time. 

The ongoing pandemic disrupts routine immunization services in many countries. When immunization services are disrupted, even for brief periods during emergencies, the risk of vaccine-preventable disease outbreaks, such as measles and polio, increase. Further disease outbreaks will also overwhelm health systems already battling the impacts of COVID-19.

WHO continues to support countries to maintain essential immunization for all vaccine preventable diseases. We issued guidance on immunization services during the COVID-19 pandemic, which provides guiding principles and considerations to support countries in their decision-making regarding provision of immunization services during the COVID-19 pandemic.

Question 1: The world is waiting for a vaccine against COVID-19. Could you explain how vaccines work to prevent disease?

Answer: Vaccination is a simple, safe, and effective way of protecting people against harmful diseases. Vaccines reduce risks of getting diseases by working with our body’s natural defences to build protection. When we get a vaccine, our immune system responds, it

• recognizes the invading germ, such as the virus or bacteria,
• produces antibodies, proteins produced naturally by the immune system to fight disease;
• remembers the disease and how to fight it. If you are then exposed to the germ in the future, your immune system can quickly destroy it before you become unwell.

Question 2: News says dozens of vaccine candidates are being research. How long does it usually take to develop a vaccine? What is the process people use to test a candidate vaccine and the process is important?

Answer: Process of vaccine development usually needs a few years or even decades. Once a promising candidate vaccine is identified in research, it will firstly undergo scrupulous laboratory testing and preclinical studies, before the manufacture can apply for clinical trials:[1]

The clinical trials are bound by strict regulations and take place across three phases:

• During Phase I, small groups (approximately 20-50 people) receive the vaccine. This phase will assess the safety, side effects, appropriate dosage, method of administration and composition of the vaccine.
• If it is successful, it will proceed to Phase II. At this stage, the vaccine is usually given to several hundred people. This group will have the same characteristics (e.g. age, sex) as the people for whom the vaccine is intended to be given.
• In Phase III, the vaccine is usually given to thousands of people to help ensure it is safe and effective for broader use.[2]

The results of all these studies will be rigorously assessed when regulators decide whether to approve a vaccine. Once a vaccine is approved for use, the vaccine must be continuously monitored to ensure the safety for the vaccinated peoples.[3]

Question 3: How do we know if vaccination will be safe? I know some people will have negative reactions after vaccination?

Answer: Vaccines approved by competent national regulatory authorities are very safe. As with all medicines, side effects can occur after getting a vaccine. However, these are usually very minor and of short duration, such as a sore arm or a mild fever. More serious side effects are possible, but extremely rare. A person is far more likely to be seriously harmed by a disease than by a vaccine.[4]

WHO works closely with national authorities to ensure that global standards are developed and made readily available to assess the quality, safety and immunogenicity of biological products including vaccines.[5]

Question 4: Have human ever successfully curb a pandemic with vaccines?

Answer: Every year, millions of lives are saved thanks to immunization and it is recognized widely as one of the most successful and cost-effective health interventions.

Last December, the world celebrated the 40^th anniversary of eradicating smallpox, which killed 300 million people in the 20th century alone. The success was attributed to an intense global smallpox vaccination campaign, in coordinated with broader public health measures.[6],[7]Today, we are seeing progress to similar success in polio. With effective polio vaccine and immunization efforts, the world has reduced wild polio cases by 99%, averting 18 million irreversible paralyze and 1.5 million children’s lives.[8]

In China, the successful childhood vaccination program has been certified wild poliovirus-free, verified maternal and neo-natal tetanus elimination in 2012, verified children under 5 were HBV-infected decreased to 0.32% in 2014, dramatically and consistently reduced vaccine-prevention diseases (VPDs) incidences to historically recorded low level by 2018 (e.g., 2.8 per million population for measles, 2.8 per million for rubella, and 1.3 per 100,000 for Japanese encephalitis), and achieved over 95% national coverage for all vaccines used for infants in 2018[9].

Question 5: What is WHO doing in accelerating the development of vaccines against COVID-19

Answer: Researchers around the world are working hard on accelerating the development of vaccines and therapeutics for COVID-19. WHO has launched various working groups to accelerate various aspects of vaccine development. A call was made by 130 scientists, funders and manufacturers to help speed the availability of a vaccine against COVID-19. More than 70 vaccines are in development globally, and several therapeutics are in clinical trials[10]. WHO is committed to ensuring that as medicines and vaccines are developed, they are shared equitably with all countries and people.

Question 6: What else can we do to protect ourselves while we are waiting for the vaccine against COVID-19?

Answer: As the response to COVID-19 continues, countries must act now protect immunization services, in order to further minimize disease outbreaks and loss of life. New WHO guidelines on immunization and COVID-19 recommend that governments temporarily pause preventive immunization campaigns where there is no active outbreak of a vaccine-preventable disease. But it urges countries prioritize the continuation of routine immunization of children in essential service delivery, as well as adult vaccinations such as influenza for groups most at risk. If immunization services must be suspended, urgent catch-up vaccinations should be rescheduled as soon as possible, prioritizing those most at risk.[11]

To date, there is no vaccine and no specific antiviral medicine to prevent or treat COVID-2019. Until specific and effective pharmaceutical interventions (e.g. therapies and vaccines) are available, people should continue to follow personal protection recommendations. At the individual level, people should follow procedures for reducing the risk of spread, such as proper hand-washing, covering your nose when sneezing, coughing into your elbow, not to touch your face, and keep practicing physical distancing.

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