Cherry-picking: The claim highlighted a few diseases where vaccines haven’t been successfully developed, but ignored the success of vaccines in preventing millions of deaths from smallpox, tuberculosis, measles, tetanus, diphtheria, among many other diseases.
BEHAUPTUNG: “No vaccine for HIV after 40 years of research. No vaccine for the common cold. No vaccine for cancer after 100 years of research. Nothing. A virus mysteriously appears and within a year a vaccine is created and we are all expected to take it. No thanks.”
REVIEW
Vaccines for COVID-19 became available to the public less than a year after the virus was first detected, much faster than any other vaccine development in history.
Some social media users have used the speed of development to imply that COVID-19 vaccines are unsafe. A post on Instagram compared it to the lack of success in finding vaccines for the human immunodeficiency virus (HIV), the common cold, and cancer.
The central idea of vaccination is to expose a person’s immune system to a marker, or antigen, that will allow it to recognize and defend better against a pathogen presenting the same antigen in the future.
Vaccines for COVID-19 were developed in record time, beating the previous fastest time of four years for a mumps vaccine in the 1960s. However, this is indicative of the unprecedented resources that governments, research funders and companies put towards completing the clinical trials; the U.S. government alone invested over $12 billion through Operation Warp Speed.
It is important to keep in mind that the speed of development didn’t compromise safety or efficacy testing of the vaccines. The COVID-19 vaccines used in the U.S. had to meet the U.S. Food and Drug Administration’s requirements for safety and efficacy before they could receive emergency use authorization.
In vaccine development, there are many stages of testing. These stages can slow down the process of vaccine development as analyzing results, deciding whether to proceed, planning the next stage, acquiring funding, gaining ethical approval, and setting up the clinical trial recruitment sites all take time.
Because of delays between each testing stage, vaccines can take many years to reach the general public. In the case of the COVID-19 vaccines, many of these stages were done in parallel to speed up the process. For instance, manufacturing plants and large-scale clinical trials were being prepared even when the vaccine was still in the early stages of safety testing.
The COVID-19 vaccine clinical trials also recruited volunteers quickly, as almost all other clinical trials stopped and the medical community focused its efforts on the pandemic. Prior to the pandemic, it could take years to recruit the thousands of people needed for clinical trials.
Another factor that sped up the clinical trials was the large number of COVID-19 infections circulating in communities around the world. Scientists running a vaccine clinical trial need to wait until there are enough infections recorded among the participants. Then they can analyze the data to see if there are fewer cases, hospitalizations or deaths in the vaccinated group compared to the group who received the placebo. If a disease is very rare or slow to develop, then it can take a long time to tell if the vaccine was effective or not. In the case of COVID-19, with hundreds of thousands of cases every day worldwide, it didn’t take long for the scientists running the clinical trials to record the required number of infections.
The COVID-19 vaccines that are authorized in the U.S. are based on either RNA or viral vector technologies that were developed over many years. These technologies allowed scientists to design the COVID-19 vaccines in a matter of weeks once the virus was identified and sequenced. Thanks to previous knowledge from the SARS and MERS outbreaks caused by similar coronaviruses, scientists knew which approaches were likely to be most effective, such as which form of antigen to use.
There are currently several effective COVID-19 vaccines in use around the world. However, their success should not be taken for granted. Many vaccine candidates failed in testing or are still under development.
Vaccines created over the last century are very successful in reducing deaths from infectious diseases. The measles vaccine alone is thought to have saved 20 million lives between 2000 and 2015, while the smallpox vaccine led to the disease’s eradication. However, some diseases, such as those referenced in the Instagram post, are more difficult to develop an effective vaccine against.
HIV
The human immunodeficiency virus (HIV) was identified in 1984 and clinical trials for the first HIV vaccine candidate opened three years later. One of the fundamental challenges with HIV is that the human immune system cannot naturally clear the infection. This makes it difficult for scientists to identify an immune response that would protect against HIV infection. Whereas vaccines for other diseases rely on triggering a similar immune response to an infection, this would not be sufficient for HIV. Within days or weeks of infection, HIV integrates its genome into the DNA of the human host cell, where it becomes invisible to the immune system and impossible to remove[1]. Due to this, there is only a brief window of time during which HIV is vulnerable to a person’s immune system.
HIV infects various immune cells and prevents the immune system from fighting the infection. HIV can also mutate rapidly, adding further difficulty to the development of an effective vaccine. Even if the immune system of an infected person could generate antibodies targeting the virus, new mutations would allow the virus to become unrecognizable again[1].
Common cold
There are at least 160 different strains of rhinoviruses, which is the group of viruses that cause up to 75 percent of common colds in adults. Developing a vaccine to protect people against even half of these strains has proved too costly or impractical so far.
Other viruses that cause the common cold include coronaviruses, adenovirus, parainfluenza viruses, respiratory syncytial virus, and metapneumovirus.
Respiratory syncytial virus (RSV) can cause serious infections in some people, increasing the risk of pneumonia and death. As described in a previous review by Health Feedback, RSV is the leading respiratory cause of hospitalization in infants and young children in the United States and the world[2,3]. According to the CDC:
“Over 57,000 hospitalizations, 500,000 emergency department visits and 1.5 million outpatient clinic visits among children <5 years of age are attributed to respiratory syncytial virus (RSV) infections each year in the United States. RSV-associated deaths among children <5 years of age are thought to be uncommon, estimated at 100-500 per year. Among US adults, an estimated 177,000 hospitalizations and 14,000 deaths associated with RSV infections occur annually. However, these are likely underestimates of RSV-associated deaths.”
An effort to develop a vaccine against RSV in the 1960s led to more severe infections among vaccinated children[4]. Research since then has identified new approaches that could avoid this problem and there are now several vaccine candidates against RSV in clinical trials that will be closely monitored for safety[5].
Cancer
Most research efforts into cancer focus on improving diagnosis, developing treatments and identifying risk factors. These advances, from new chemotherapies to reductions in smoking, have significantly reduced deaths, after adjusting for age, over the last 25 years[6].
However, vaccines are effective at preventing some types of cancer. For example, a vaccine against human papillomavirus (HPV) prevents most cases of cervical cancer.
Cancer vaccines are also in the early stages of development as a form of treatment, rather than disease prevention. The aim of this new approach is to trigger a person’s immune system to attack the cancer cells, potentially treating cancers that are currently incurable.
Conclusion
The COVID-19 vaccines were created and tested more quickly than any vaccine in history. This was due to advances in vaccine technology, scientists’ improved understanding of the immune response to viruses, and unprecedented resources that were made available by governments and companies. The COVID-19 vaccines went through the same degree of testing as would be expected of any vaccine to demonstrate their relative efficacy and safety. Effective vaccines against some other diseases, such as HIV, are much more difficult to create despite decades of research.
REFERENCES
- 1 – Johnston and Fauci (2008) An HIV Vaccine — Challenges and Prospects. New England Journal of Medicine.
- 2 – Hall (2010) Respiratory syncytial virus in young children. Lancet.
- 3 – Nair et al. (2010) Global burden of acute lower respiratory infections due to respiratory syncytial virus in young children: a systematic review and meta-analysis. Lancet.
- 4 – Acosta et al. (2016) Brief History and Characterization of Enhanced Respiratory Syncytial Virus Disease. Clinical and Vaccine Immunology.
- 5 – Mazur et al. (2018) The respiratory syncytial virus vaccine landscape: lessons from the graveyard and promising candidates. The Lancet Infectious Diseases.
- 6 – Arnold et al. (2019) Progress in cancer survival, mortality, and incidence in seven high-income countries 1995–2014 (ICBP SURVMARK-2): a population-based study. The Lancet Oncology.
