This explainer is more than 90 days old. Some of the information might be out of date or no longer relevant. Browse our homepage for up to date content or request information about a specific topic from our team of scientists.
This article has been translated from its original language. Please reach out if you have any feedback on the translation.
Standard vaccine development is a long process. Multiple studies on safety often take place over multiple years. Manufacturers use phased testing to determine an effective vaccine dose and to evaluate if the vaccine works, if it’s safe, if it has significant or serious side effects, and if immune systems respond well to the vaccine. To pursue regulatory authorization, a vaccine’s benefits must be shown to be greater than its risks, and vaccine safety and effectiveness are considered to be top priorities by regulatory agencies. Regulators around the world oversee vaccine development and testing at both national and international levels. In the European Union (EU), the European Medicines Agency (EMA) has a COVID-19 Task Force (COVID-ETF) that takes “quick and coordinated regulatory action on the development, authorization, and safety monitoring” for medicines and vaccines to treat and prevent COVID-19. In the US, the Food and Drug Administration (FDA) Center for Biologics Evaluation and Research (CBER) ensures that “rigorous scientific and regulatory processes are followed by those who pursue the development of vaccines.” Similar to the COVID-ETF in Europe, the FDA has also recruited experts from government agencies, academia, nonprofit organizations, pharmaceutical companies, and international partners to “develop a coordinated strategy for prioritizing and speeding development of the most promising treatments and vaccines.” To facilitate timely vaccine development during health crises, the US FDA sets clinical trial standards for scientific data on safety and efficacy, which manufacturers need to achieve in order to bring a vaccine to the US population. Once manufacturers meet those criteria, companies can pursue Emergency Use Authorization (EUA) approval, through which the manufacturer’s EUA submission is reviewed by FDA career scientists and physicians. So far, Moderna and Pfizer have both submitted data on their vaccines for FDA EUA approval. While some COVID-19 vaccine manufacturers have requested emergency authorization with regulatory agencies around the world, it is important to note that if emergency authorization is approved, it is generally considered to be an emergency exception, with temporary permissions designed to accommodate the current COVID-19 public health crisis. Emergency authorization is not the same as formal licensing, which can take months. Unlicensed vaccines may be authorized by regulatory agencies and their lack of licensing does not mean that the vaccine has not been rigorously tested. Because of the nature of pandemic circumstances, for emergency authorizations, governmental agencies rather than manufacturers often assume responsibility for vaccine safety. In the US, for example, the Public Readiness and Emergency Preparedness Act (PREP Act) provides manufacturers, distributors, and others with liability immunity, as long as they have not participated in “willful misconduct.” Regulatory oversight and monitoring will continue even once vaccines are approved for emergency use. In addition to testing by the vaccine manufacturers, government regulators regularly test vaccines for quality, and tweak manufacturing once they are released onto the market. Post-authorization, US vaccine safety monitoring is performed by the federal government (US FDA and the US Centers for Disease Control and Prevention [CDC]) and other agencies and organizations who are involved in healthcare delivery. Vaccine safety and monitoring systems are in place to quickly identify rare side effects that were not identified in clinical trials, and to detect possible vaccine safety problems. Though no major safety concerns have been identified in the current vaccine trials, even when the current clinical trials are completed pharmaceutical companies, regulatory agencies, public health experts, researchers, and others will continue to evaluate safety, efficacy, effectiveness, and side effects in the years to come. The US FDA has stated that “efforts to speed vaccine development to address the ongoing COVID-19 pandemic have not sacrificed scientific standards, integrity of the vaccine review process, or safety.”
Standard vaccine development is a long process. Multiple studies on safety often take place over multiple years. Manufacturers use phased testing to determine an effective vaccine dose and to evaluate if the vaccine works, if it’s safe, if it has significant or serious side effects, and if immune systems respond well to the vaccine. To pursue regulatory authorization, a vaccine’s benefits must be shown to be greater than its risks, and vaccine safety and effectiveness are considered to be top priorities by regulatory agencies. Regulators around the world oversee vaccine development and testing at both national and international levels. In the European Union (EU), the European Medicines Agency (EMA) has a COVID-19 Task Force (COVID-ETF) that takes “quick and coordinated regulatory action on the development, authorization, and safety monitoring” for medicines and vaccines to treat and prevent COVID-19. In the US, the Food and Drug Administration (FDA) Center for Biologics Evaluation and Research (CBER) ensures that “rigorous scientific and regulatory processes are followed by those who pursue the development of vaccines.” Similar to the COVID-ETF in Europe, the FDA has also recruited experts from government agencies, academia, nonprofit organizations, pharmaceutical companies, and international partners to “develop a coordinated strategy for prioritizing and speeding development of the most promising treatments and vaccines.” To facilitate timely vaccine development during health crises, the US FDA sets clinical trial standards for scientific data on safety and efficacy, which manufacturers need to achieve in order to bring a vaccine to the US population. Once manufacturers meet those criteria, companies can pursue Emergency Use Authorization (EUA) approval, through which the manufacturer’s EUA submission is reviewed by FDA career scientists and physicians. So far, Moderna and Pfizer have both submitted data on their vaccines for FDA EUA approval. While some COVID-19 vaccine manufacturers have requested emergency authorization with regulatory agencies around the world, it is important to note that if emergency authorization is approved, it is generally considered to be an emergency exception, with temporary permissions designed to accommodate the current COVID-19 public health crisis. Emergency authorization is not the same as formal licensing, which can take months. Unlicensed vaccines may be authorized by regulatory agencies and their lack of licensing does not mean that the vaccine has not been rigorously tested. Because of the nature of pandemic circumstances, for emergency authorizations, governmental agencies rather than manufacturers often assume responsibility for vaccine safety. In the US, for example, the Public Readiness and Emergency Preparedness Act (PREP Act) provides manufacturers, distributors, and others with liability immunity, as long as they have not participated in “willful misconduct.” Regulatory oversight and monitoring will continue even once vaccines are approved for emergency use. In addition to testing by the vaccine manufacturers, government regulators regularly test vaccines for quality, and tweak manufacturing once they are released onto the market. Post-authorization, US vaccine safety monitoring is performed by the federal government (US FDA and the US Centers for Disease Control and Prevention [CDC]) and other agencies and organizations who are involved in healthcare delivery. Vaccine safety and monitoring systems are in place to quickly identify rare side effects that were not identified in clinical trials, and to detect possible vaccine safety problems. Though no major safety concerns have been identified in the current vaccine trials, even when the current clinical trials are completed pharmaceutical companies, regulatory agencies, public health experts, researchers, and others will continue to evaluate safety, efficacy, effectiveness, and side effects in the years to come. The US FDA has stated that “efforts to speed vaccine development to address the ongoing COVID-19 pandemic have not sacrificed scientific standards, integrity of the vaccine review process, or safety.”
Standard vaccine development is a long process. Multiple studies on safety often take place over multiple years. Manufacturers use phased testing to determine an effective vaccine dose and to evaluate if the vaccine works, if it’s safe, if it has significant or serious side effects, and if immune systems respond well to the vaccine. To pursue regulatory authorization, a vaccine’s benefits must be shown to be greater than its risks, and vaccine safety and effectiveness are considered to be top priorities by regulatory agencies.
Regulators around the world oversee vaccine development and testing at both national and international levels. In the European Union (EU), the European Medicines Agency (EMA) has a COVID-19 Task Force (COVID-ETF) that takes “quick and coordinated regulatory action on the development, authorization, and safety monitoring” for medicines and vaccines to treat and prevent COVID-19. In the US, the Food and Drug Administration (FDA) Center for Biologics Evaluation and Research (CBER) ensures that “rigorous scientific and regulatory processes are followed by those who pursue the development of vaccines.” Similar to the COVID-ETF in Europe, the FDA has also recruited experts from government agencies, academia, nonprofit organizations, pharmaceutical companies, and international partners to “develop a coordinated strategy for prioritizing and speeding development of the most promising treatments and vaccines.”
To facilitate timely vaccine development during health crises, the US FDA sets clinical trial standards for scientific data on safety and efficacy, which manufacturers need to achieve in order to bring a vaccine to the US population. Once manufacturers meet those criteria, companies can pursue Emergency Use Authorization (EUA) approval, through which the manufacturer’s EUA submission is reviewed by FDA career scientists and physicians. So far, Moderna and Pfizer have both submitted data on their vaccines for FDA EUA approval.
While some COVID-19 vaccine manufacturers have requested emergency authorization with regulatory agencies around the world, it is important to note that if emergency authorization is approved, it is generally considered to be an emergency exception, with temporary permissions designed to accommodate the current COVID-19 public health crisis.
Emergency authorization is not the same as formal licensing, which can take months. Unlicensed vaccines may be authorized by regulatory agencies and their lack of licensing does not mean that the vaccine has not been rigorously tested.
Because of the nature of pandemic circumstances, for emergency authorizations, governmental agencies rather than manufacturers often assume responsibility for vaccine safety. In the US, for example, the Public Readiness and Emergency Preparedness Act (PREP Act) provides manufacturers, distributors, and others with liability immunity, as long as they have not participated in “willful misconduct.”
Regulatory oversight and monitoring will continue even once vaccines are approved for emergency use. In addition to testing by the vaccine manufacturers, government regulators regularly test vaccines for quality, and tweak manufacturing once they are released onto the market.
Post-authorization, US vaccine safety monitoring is performed by the federal government (US FDA and the US Centers for Disease Control and Prevention [CDC]) and other agencies and organizations who are involved in healthcare delivery. Vaccine safety and monitoring systems are in place to quickly identify rare side effects that were not identified in clinical trials, and to detect possible vaccine safety problems.
Though no major safety concerns have been identified in the current vaccine trials, even when the current clinical trials are completed pharmaceutical companies, regulatory agencies, public health experts, researchers, and others will continue to evaluate safety, efficacy, effectiveness, and side effects in the years to come. The US FDA has stated that “efforts to speed vaccine development to address the ongoing COVID-19 pandemic have not sacrificed scientific standards, integrity of the vaccine review process, or safety.”
Standard vaccine development is a long process. Multiple studies on safety often take place over multiple years. Manufacturers use phased testing to determine an effective vaccine dose and to evaluate if the vaccine works, if it’s safe, if it has significant or serious side effects, and if immune systems respond well to the vaccine. To pursue regulatory authorization, a vaccine’s benefits must be shown to be greater than its risks, and vaccine safety and effectiveness are considered to be top priorities by regulatory agencies.
Regulators around the world oversee vaccine development and testing at both national and international levels. In the European Union (EU), the European Medicines Agency (EMA) has a COVID-19 Task Force (COVID-ETF) that takes “quick and coordinated regulatory action on the development, authorization, and safety monitoring” for medicines and vaccines to treat and prevent COVID-19. In the US, the Food and Drug Administration (FDA) Center for Biologics Evaluation and Research (CBER) ensures that “rigorous scientific and regulatory processes are followed by those who pursue the development of vaccines.” Similar to the COVID-ETF in Europe, the FDA has also recruited experts from government agencies, academia, nonprofit organizations, pharmaceutical companies, and international partners to “develop a coordinated strategy for prioritizing and speeding development of the most promising treatments and vaccines.”
To facilitate timely vaccine development during health crises, the US FDA sets clinical trial standards for scientific data on safety and efficacy, which manufacturers need to achieve in order to bring a vaccine to the US population. Once manufacturers meet those criteria, companies can pursue Emergency Use Authorization (EUA) approval, through which the manufacturer’s EUA submission is reviewed by FDA career scientists and physicians. So far, Moderna and Pfizer have both submitted data on their vaccines for FDA EUA approval.
While some COVID-19 vaccine manufacturers have requested emergency authorization with regulatory agencies around the world, it is important to note that if emergency authorization is approved, it is generally considered to be an emergency exception, with temporary permissions designed to accommodate the current COVID-19 public health crisis.
Emergency authorization is not the same as formal licensing, which can take months. Unlicensed vaccines may be authorized by regulatory agencies and their lack of licensing does not mean that the vaccine has not been rigorously tested.
Because of the nature of pandemic circumstances, for emergency authorizations, governmental agencies rather than manufacturers often assume responsibility for vaccine safety. In the US, for example, the Public Readiness and Emergency Preparedness Act (PREP Act) provides manufacturers, distributors, and others with liability immunity, as long as they have not participated in “willful misconduct.”
Regulatory oversight and monitoring will continue even once vaccines are approved for emergency use. In addition to testing by the vaccine manufacturers, government regulators regularly test vaccines for quality, and tweak manufacturing once they are released onto the market.
Post-authorization, US vaccine safety monitoring is performed by the federal government (US FDA and the US Centers for Disease Control and Prevention [CDC]) and other agencies and organizations who are involved in healthcare delivery. Vaccine safety and monitoring systems are in place to quickly identify rare side effects that were not identified in clinical trials, and to detect possible vaccine safety problems.
Though no major safety concerns have been identified in the current vaccine trials, even when the current clinical trials are completed pharmaceutical companies, regulatory agencies, public health experts, researchers, and others will continue to evaluate safety, efficacy, effectiveness, and side effects in the years to come. The US FDA has stated that “efforts to speed vaccine development to address the ongoing COVID-19 pandemic have not sacrificed scientific standards, integrity of the vaccine review process, or safety.”
Vaccines play an essential role in protecting the public's health, especially when there is limited treatment available for a disease. With COVID-19 cases still rising in several countries, many people are looking to vaccines as a crucial step towards ending the pandemic and pandemic-related economic restrictions.
There is immense public, political and commercial pressure for COVID-19 vaccines to be developed, tested, approved, manufactured, and distributed with unprecedented speed. Although COVID-19 only emerged about a year ago and vaccine development has historically taken years or even decades, COVID-19 vaccine development has been accelerated, with many phases of testing, and ramp-up for manufacturing, happening simultaneously around the world for the first time at this scale.
With the increased complexity of accelerated vaccine development and so many forces pushing for COVID-19 vaccine candidates to enter the market as soon as possible, regulatory checks and balances are critically important to ensure that vaccines are safe as well as effective, and that manufacturing quality is consistent. These standards can be challenging to maintain. In September 2020, leading U.S. and European vaccine developers (including Pfizer, GlaxoSmithKline, and AstraZeneca) made what they called a “historic pledge” to maintain rigor after concerns that “safety and efficacy standards might slip in the rush to find a vaccine.”
Additionally, the processes and timelines for vaccine approval and distribution vary significantly from country to country. For example, Russia surprised the global community by approving their first vaccine candidate in August 2020 based on limited preliminary results that would not have satisfied many other international standards. China began vaccinating hundreds of thousands of people in the summer and fall of 2020 through "emergency use" of experimental vaccine candidates before regulatory approval for public use, with some criticism because COVID-19 cases were down in China at that time. As a result, there were questions about whether China had an unreported emergency justifying the early vaccinations or whether China was allowing other interests to override public health interests.
Public health concerns over early vaccinations include not only the risks of side effects, but also vaccine recipients potentially feeling invincible and further contributing to the spread of disease if an early vaccine turns out to be less effective than clinical trials indicate. Trials have typically tested vaccines with a less diverse population than the general public, so it is important to check that vaccines are safe for everyone including minorities and people with pre-existing conditions before widespread deployment. In rare cases, antibodies from new vaccines could even lead to severe disease in certain recipients, such as what happened during testing of experimental vaccines for Severe Acute Respiratory Syndrome (SARS). There are concerns that premature vaccinations could lead to more issues arising, eroding the public’s trust and leading to more hesitance around vaccinations in the future.
Researchers and doctors have warned that COVID-19 vaccine deployment should not be driven by commercial interests, and are urging patience for the necessary processes of checking that vaccines are safe and effective for the general public. Fortunately, most safety issues identified in the COVID-19 vaccine trials so far have been minor and several vaccine candidates are getting closer to being ready for commercial deployment.
Vaccines play an essential role in protecting the public's health, especially when there is limited treatment available for a disease. With COVID-19 cases still rising in several countries, many people are looking to vaccines as a crucial step towards ending the pandemic and pandemic-related economic restrictions.
There is immense public, political and commercial pressure for COVID-19 vaccines to be developed, tested, approved, manufactured, and distributed with unprecedented speed. Although COVID-19 only emerged about a year ago and vaccine development has historically taken years or even decades, COVID-19 vaccine development has been accelerated, with many phases of testing, and ramp-up for manufacturing, happening simultaneously around the world for the first time at this scale.
With the increased complexity of accelerated vaccine development and so many forces pushing for COVID-19 vaccine candidates to enter the market as soon as possible, regulatory checks and balances are critically important to ensure that vaccines are safe as well as effective, and that manufacturing quality is consistent. These standards can be challenging to maintain. In September 2020, leading U.S. and European vaccine developers (including Pfizer, GlaxoSmithKline, and AstraZeneca) made what they called a “historic pledge” to maintain rigor after concerns that “safety and efficacy standards might slip in the rush to find a vaccine.”
Additionally, the processes and timelines for vaccine approval and distribution vary significantly from country to country. For example, Russia surprised the global community by approving their first vaccine candidate in August 2020 based on limited preliminary results that would not have satisfied many other international standards. China began vaccinating hundreds of thousands of people in the summer and fall of 2020 through "emergency use" of experimental vaccine candidates before regulatory approval for public use, with some criticism because COVID-19 cases were down in China at that time. As a result, there were questions about whether China had an unreported emergency justifying the early vaccinations or whether China was allowing other interests to override public health interests.
Public health concerns over early vaccinations include not only the risks of side effects, but also vaccine recipients potentially feeling invincible and further contributing to the spread of disease if an early vaccine turns out to be less effective than clinical trials indicate. Trials have typically tested vaccines with a less diverse population than the general public, so it is important to check that vaccines are safe for everyone including minorities and people with pre-existing conditions before widespread deployment. In rare cases, antibodies from new vaccines could even lead to severe disease in certain recipients, such as what happened during testing of experimental vaccines for Severe Acute Respiratory Syndrome (SARS). There are concerns that premature vaccinations could lead to more issues arising, eroding the public’s trust and leading to more hesitance around vaccinations in the future.
Researchers and doctors have warned that COVID-19 vaccine deployment should not be driven by commercial interests, and are urging patience for the necessary processes of checking that vaccines are safe and effective for the general public. Fortunately, most safety issues identified in the COVID-19 vaccine trials so far have been minor and several vaccine candidates are getting closer to being ready for commercial deployment.