Five Things We Know and Don’t Know About COVID-19, Five Years After Its Emergence
Five years ago, a mysterious illness appeared in Wuhan, China, and set off a pandemic that reshaped the world. While humanity has made significant progress in understanding and managing the virus, many questions remain unanswered. Here, we explore what we’ve learned and the mysteries that still surround COVID-19.
The Origins of the Virus
COVID-19’s origins remain a hotly debated topic. Scientists generally agree that the virus likely originated in bats, similar to other coronaviruses. The prevailing theory suggests that the virus jumped from bats to another species, such as raccoon dogs, civet cats, or bamboo rats, before infecting humans. This transmission likely occurred in a market in Wuhan, where the first human cases were detected in late 2019.
However, this theory has not been definitively proven. Wuhan is also home to several research laboratories studying coronaviruses, leading to speculation about a potential lab leak. Efforts to pinpoint the virus’s origins have been complicated by political tensions and limited access to critical evidence from China. The true origin may remain a mystery for years, if not forever.
The Global Death Toll
The official death toll reported by the World Health Organization (WHO) stands at over 7 million, but the actual number is likely much higher. Experts estimate that the true death toll is at least three times the reported figure, potentially exceeding 20 million globally. This discrepancy underscores the challenges in accurately counting deaths during a pandemic, especially in regions with limited healthcare infrastructure.
In the United States, COVID-19 remains a significant cause of mortality, particularly among older adults. Over the past year, an average of 900 people per week have succumbed to the virus, according to the Centers for Disease Control and Prevention (CDC). Older individuals, especially those aged 75 and above, continue to bear the brunt of severe illness and fatalities.
Vaccine Development and Impact
One of the pandemic’s silver linings has been the unprecedented speed of vaccine development. Scientists and pharmaceutical companies achieved what was previously thought impossible: creating effective COVID-19 vaccines in under a year. By late 2020, vaccines from Pfizer-BioNTech and Moderna had received emergency use authorization in the United States and other countries.
This rapid progress was built on years of prior research, including breakthroughs in mRNA technology. Since then, over 13 billion doses of COVID-19 vaccines have been administered worldwide, saving millions of lives and helping to bring the pandemic under control. Traditional vaccines, such as Novavax’s option, have also been developed and deployed.
However, vaccines are not without limitations. While they provide strong protection against severe illness and death, their effectiveness against mild infections wanes over time. Like influenza vaccines, COVID-19 shots require periodic updates to combat emerging variants, which has led to public fatigue over repeated vaccinations. Researchers are now working on next-generation vaccines, including nasal sprays that could potentially block infections more effectively.
The Evolution of the Virus
COVID-19 has demonstrated an extraordinary ability to mutate. The virus’s evolution has been marked by the emergence of variants named after Greek letters, including alpha, beta, gamma, delta, and omicron. Each variant brought unique challenges, with some causing more severe illness or spreading more rapidly than others.
Delta, which became dominant in mid-2021, was particularly concerning due to its higher likelihood of causing severe disease. However, it was soon overshadowed by omicron, a variant that spread at an unprecedented rate but generally caused less severe illness. Scientists attribute this to a combination of factors, including growing population immunity from vaccines and prior infections.
Today, omicron subvariants dominate globally, with the U.S. currently seeing the prevalence of a subvariant called XEC. Existing vaccines and treatments appear effective against these newer strains, although the virus’s constant evolution necessitates ongoing vigilance and adaptation.
The Enigma of Long COVID
One of the pandemic’s most perplexing legacies is long COVID. This condition affects millions of people worldwide, leaving them with persistent symptoms that can last for months or even years. Common symptoms include fatigue, brain fog, pain, and cardiovascular issues.
Long COVID can develop after mild infections and affects people of all ages, although its prevalence has declined over time. Vaccination has been shown to reduce the risk of long COVID, but it does not eliminate it entirely. Researchers are still trying to unravel the condition’s underlying causes, with one prominent theory pointing to lingering remnants of the virus in the body. However, this explanation does not account for all cases, complicating efforts to develop effective treatments.