The pandemic unleashed a cascade of economic and social upheaval that reshaped lives across the globe. Tens of millions faced the threat of extreme poverty as jobs vanished and incomes plummeted, particularly in vulnerable communities
and informal economies where social protections were scarce. Food insecurity surged, with nearly 690 million people undernourished and projections suggesting up to 132 million more could be added to that grim tally1. The crisis exposed the
fragility of global food systems, disrupted supply chains, and left agricultural workers struggling to access markets and harvest crops. Inequality widened dramatically, with women, youth, and low-education workers bearing the brunt of job
losses. Meanwhile, the strain on public health systems and the rise of long-term health complications added another layer of hardship, especially for marginalized populations. The pandemic didn’t just test resilience—it redefined it.
As of August 2025, COVID-19 continues to show troubling momentum across the United States. According to CDC modeling, infections are growing or likely growing in 34 states, with no states seeing a decline, and 14 remaining unchanged.
This surge is driven by highly transmissible variants like NB.1.8.1 (“Nimbus”) and XFG (“Stratus”), which have evolved to better evade immunity and are fueling a summer wave of cases. Emergency department visits and hospitalizations are
climbing, especially in densely populated regions such as California, Texas, and Florida. Despite years of vaccination and public health efforts, the virus remains a persistent and adaptive threat.
On May 5, 2023, the World Health Organization (WHO) officially declared that COVID-19 no longer constitutes a public health emergency of international concern—the highest level of global health alert. This decision was based on a
sustained decline in COVID-19-related deaths, hospitalizations, and ICU admissions, as well as increased population immunity from widespread vaccination and prior infections. However, this shift doesn't mean the virus has vanished.
COVID-19 remains a global health threat, with new variants still emerging and thousands of deaths reported weekly. The WHO emphasized that the pandemic is transitioning into a long-term management phase, where COVID-19 is treated more
like other endemic respiratory illnesses. In essence, the emergency phase has ended, but the vigilance continues.
Long COVID remains a medical mystery without a definitive cure, but the global research effort to crack its code is intensifying. Scientists have identified over 200 symptoms—from brain fog and fatigue to heart palpitations and
digestive issues—making treatment a complex puzzle. Management today relies on personalized care: medications to ease symptoms, physical therapy to rebuild strength, counseling to support mental health, and emerging immunotherapies
that aim to reset the body’s response. Promising trials, like those testing Anktiva and baricitinib, are exploring whether immune modulation can reverse the lingering effects. Yet, a major hurdle persists: the lack of a universal
definition. With different studies using different criteria, diagnosis and treatment remain inconsistent. Until science catches up, long COVID is treated more like a chronic condition—managed, not cured, with hope riding on the
next breakthrough.
COVID-19 dealt its harshest blow to older adults, with more than 81% of deaths occurring in those over age 65—a staggering mortality rate nearly 100 times higher than among young adults aged 18 to 29. Age alone emerged as the strongest
predictor of severe outcomes, but the danger deepened with each underlying medical condition. Chronic illnesses like heart disease, diabetes, obesity, and lung disorders compounded the risk, turning a mild infection into a life-threatening
crisis. The virus didn’t just exploit age—it preyed on vulnerability, disproportionately affecting those with weakened immune systems and complex health profiles. Seniors with multiple conditions faced a perfect storm, where even a brief
exposure could spiral into hospitalization, intensive care, or death.
COVID-19 isn’t just a fleeting illness—it can leave a trail of complications that linger long after the fever fades. From the eerie disappearance of taste and smell to stubborn skin rashes and painful sores, the virus has a knack
for disrupting the senses. Breathing can become a daily struggle, with some developing pneumonia or lasting lung damage. It doesn’t stop there: pre-existing conditions like diabetes or asthma may flare up, and new ones—like chronic
fatigue or heart issues—can emerge out of nowhere. Some people report brain fog, anxiety, and even vascular aging, especially in women. And just when you think it’s over, long COVID might throw in joint pain, digestive chaos, or insomnia
for good measure. It’s a reminder that this virus isn’t just a short-term guest—it can be a long-haul intruder.
COVID-19 unleashed a global shockwave that rippled far beyond hospitals and ICUs, shaking economies, deepening inequality, and unraveling social safety nets. The pandemic triggered the largest economic crisis in over a century,
slashing global GDP by 3.4% in 2020—translating to trillions in lost output. Tens of millions were pushed to the brink of extreme poverty, and hunger surged, with nearly 690 million undernourished people facing the threat of an additional
132 million joining their ranks. Emerging economies were hit hardest, where fragile financial systems and limited social protections left households and businesses unable to weather prolonged income losses. Women, youth, and informal
workers bore the brunt, especially in sectors crippled by lockdowns and distancing measures. Even as recovery began, it remained uneven and fragile, shadowed by rising debt, inflationary pressures, and the lingering specter of new variants.
The pandemic didn’t just disrupt—it exposed and widened the fault lines of global inequality.
COVID-19’s global saga began with the naming of SARS-CoV-2, the virus behind the outbreak, and escalated rapidly when the World Health Organization (WHO) declared a pandemic in March 2020. What followed was a whirlwind of lockdowns,
overwhelmed hospitals, vaccine breakthroughs, and shifting public health strategies. After more than three years of relentless waves and evolving variants, the WHO officially declared the end of the public health emergency of international
concern in May 2023. While this marked a turning point, it didn’t mean the virus vanished—COVID-19 transitioned from a global emergency to an ongoing health challenge, with localized surges and long-term effects still shaping lives and
policies around the world.
Meningococcal meningitis is a bacterial form of meningitis, a serious infection of the thin lining that surrounds the brain and spinal cord.
It's a severe bacterial infection caused by Neisseria meningitidis, which inflames the meninges, the protective membranes around the brain and spinal cord. Meningococcal meningitis spreads through respiratory droplets or close contact,
like coughing, kissing, or sharing utensils. While it’s relatively rare in places like the U.S., it can progress rapidly and be life-threatening without prompt treatment. Symptoms often include sudden fever, headache, stiff neck, nausea,
confusion, and sometimes a purplish rash. In severe cases, it can lead to sepsis, brain damage, or death. Fortunately, vaccines are available and are especially recommended for adolescents and travelers to regions where the disease
is more common.
The diseases that have killed the most humans in history are 1918 Spanish flu, Black Death, HIV/AIDS pandemic, Plague of Justinian (541–549), and COVID-19; those pandemics are among the deadliest in human history.
1918 “Spanish” Flu - Caused by an H1N1 influenza virus, it killed between 17 and 100 million people globally between 1918 and 1920, making it the deadliest pandemic in recorded history.
Black Death (1346–1353) - This outbreak of bubonic plague swept through Europe, Asia, and North Africa, killing an estimated 25 to 50 million people, or up to 60% of Europe’s population at the time.
HIV/AIDS Pandemic - Since it began in the early 1980s, HIV/AIDS has claimed around 44 million lives worldwide as of 2025, and it remains an ongoing global health crisis.
Plague of Justinian (541–549) - Estimated 15–100 million deaths.
COVID-19 - As of 2025, estimated to have caused between 7.1 and 36.5 million deaths globally.
Black Death, Spanish Flu, Plague of Justinian, HIV/AIDS Pandemic, and COVID-19 Pandemic are the most deadliest pandemics in history; these pandemics had devastating effects on global populations, reshaping societies and economies.
Black Death (1347-1351) – Estimated 200 million deaths worldwide, caused by the bubonic plague.
Spanish Flu (1918-1920) – Estimated 17-100 million deaths, caused by the H1N1 influenza virus.
Plague of Justinian (541-549) – Estimated 15-100 million deaths, caused by the bubonic plague.
HIV/AIDS Pandemic (1981-present) – Estimated 44 million deaths as of 2025.
COVID-19 Pandemic (2019-present) – Estimated 7.1-36.5 million deaths as of 2025.
COVID-19, Ebola, Malaria, Tuberculosis (TB), HIV/AIDS, Influenza (Flu), Zika Virus, Dengue Fever, Cholera, and Rabies are considered highly dangerous due to their high mortality rates, rapid spread, or lack of effective treatments. These diseases pose significant health risks and require ongoing efforts for prevention, treatment, and control.
COVID-19 (coronavirus disease 2019): A disease caused by a virus named SARS-CoV-2; it's very contagious and spreads quickly, and has led to a global pandemic with millions of deaths worldwide in 2019.
Ebola: A disease caused a severe and often fatal illness, primarily affecting humans and nonhuman primates; this disease caused by a group of viruses, known as orthoebolaviruses (formally ebolavirus).
Malaria: Transmitted by mosquitoes, it is a major cause of death in many tropical and subtropical regions.
Tuberculosis (TB): A bacterial infection that primarily affects the lungs and can be fatal if not treated properly.
HIV/AIDS: A virus that attacks the immune system, leading to a range of serious health issues and potentially death.
Influenza (Flu): A highly contagious respiratory illness that can cause severe complications, especially in vulnerable populations.
Zika Virus: Spread by mosquitoes, it can cause birth defects and neurological complications.
Dengue Fever: Another mosquito-borne illness, it can lead to severe flu-like symptoms and potentially fatal complications.
Cholera: A bacterial infection causing severe diarrhea and dehydration, which can be fatal without prompt treatment.
Rabies: A viral disease that causes inflammation of the brain and is almost always fatal once symptoms appear.
Contracting COVID-19 may trigger the body’s natural defenses, producing antibodies that offer some future protection—but that immunity comes at a dangerous price. Severe illness, lingering health problems, and even death remain real risks,
making infection a perilous path to resilience. While studies suggest that natural immunity can rival vaccine-induced protection in certain cases, the unpredictability of the virus makes this route far from ideal. Vaccination, by contrast,
provides a safer and more controlled way to build immunity, sidestepping the roulette wheel of complications that COVID-19 so often spins.
Getting a COVID-19 vaccine is a safer and more dependable way to build immunity to COVID-19 than getting sick with COVID-19. Nearly all the ingredients in
COVID-19 vaccines are also ingredients (e.g., fats, sugars, salts) in many foods; none of the COVID-19 vaccines contain ingredients like preservatives, tissues (such as aborted fetal
cells), antibiotics, food proteins, medicines, latex, or metals.
Despite widespread vaccination efforts in the U.S.—with roughly 80% of the population having received at least one dose, 68% fully vaccinated,
and 34% boosted—the toll of COVID-19 remained sobering as of February 2023. The virus was still claiming over 450 lives daily, a staggering figure that dwarfed the average number of deaths from car accidents nearly fourfold. This contrast
underscores the persistent danger of the pandemic, even in a landscape shaped by vaccines and public health campaigns. It’s a stark reminder that immunity, whether natural or vaccine-induced, doesn’t guarantee invincibility—and that the virus
continues to exploit gaps in protection, especially among vulnerable populations.
In the early months of 2023, COVID-19 was still claiming around 450 lives per day in the U.S.—a sobering reminder that the virus hadn’t faded quietly. That daily toll was notably higher than in December 2022, when the average hovered
around 250 deaths per day, but far below the staggering peak of 3,200 daily deaths during the height of the Omicron wave in 2021. By 2025, COVID-19 has transitioned into an endemic phase, yet it continues to cause thousands of preventable
deaths each month, particularly among older adults and immunocompromised individuals. The virus’s persistence, fueled by emerging subvariants like JN.1 and KP.2, underscores the need for ongoing vigilance—even as the emergency phase fades
into history.
Since the coronavirus first emerged in Wuhan, China, in 2019, according to data compiled by Johns Hopkins University, it has killed more than 487,000,000 people as of October 2021, and more than 239 million cases have been reported. In September
2021, the U.S. death toll surpassed 700,000, and has continued to have the highest cumulative number of confirmed cases and deaths globally. India has accounted for about
1 in 3 of all new confirmed cases, and in May 2021 it set records for the number
of new daily deaths with more than 4,500 deaths from COVID-19 reported in a single
24-hour period. The COVID-19 vaccines were developed and rolled out at record speed, billions of doses have been administered
around the world, and studies show most have impressive efficacy. China now leads the world in the number of vaccine doses given out, though
some other nations have vaccinated a greater share of their population.
A study backed by the U.S. Food and Drug Administration (FDA), vaccines for COVID-19 and influenza may slightly increase the risk of strokes caused by
blood clots in the brains of older adults, particularly when these two vaccines are given at the same time to senior who are age 85 and older at the same time.
People with a disability (e.g., asthma, chronic kidney disease, chronic obstructive pulmonary disease, diabetes) are twice as likely to report having long COVID than those without.
These adults have long COVID-19 symptoms, including fatigue, gastrointestinal issues, rapid heartbeat, memory loss, cough, chest pain, skin rashes, difficulty exercising, anxiety, trouble sleeping, depression, trouble focusing, dizziness,
that lasted three months or longer.
The first COVID-19 vaccines began rolling out less than a year into the pandemic. While vaccine development typically has 5 steps
(clinical trials phase 1, phase 2 and phase 3, regulatory approval and manufacturing), and takes one step at a time, which requires 5 years to 15 years to complete, COVID-19 vaccines development has multiple steps happening at once and only takes
between 1 year to 2 years for completion. But the COVID-19 vaccines have been held to the same safety standards as any other vaccine — and rigorous clinical trials have proven that they’re
safe and effective.
Pfizer-BioNTech,
Moderna,
Johnson & Johnson’s Janssen, and
Oxford Astrazeneca were
approved COVID-19 vaccines for use in the US. Studies show that these COVID-19 vaccines are effective at keeping people from getting COVID-19. The other COVID-19 vaccines that do not properly follow the vaccine development procedures, such as
Sinovac and
Sinopharm, were also recommended for emergency use by WHO Strategic Advisory Group of Experts on
Immunization (SAGE).
Around 80% of people with coronavirus disease 2019 (COVID-19) recovered without needing any specialist treatment. For these people, this new
coronavirus caused mild or moderate symptoms, such as fever and cough, that clear up in 2 to 3 weeks. For some people, especially older adults
(65 years and older) and people with existing health problems or serious underlying medical conditions (e.g.; chronic lung disease, asthma, heart conditions, cancer, diabetes, renal failure, and liver disease) might be at
higher risk for pneumonia
and death from COVID-19.
Some 86% of people with mild cases of COVID-19 lose their sense of smell and taste but recover it within six months, according to a study of more than 2,500 patients from 18 European hospitals. That stat paints a vivid picture of just how
common sensory disruption is in mild COVID-19 cases. According to a large-scale study involving over 2,500 patients across 18 European hospitals, a striking 86% of those with mild infections reported losing their sense of smell and taste—but the
silver lining is that most regained these senses within six months. This recovery trend offers hope, especially considering how unsettling and disorienting sensory loss can be. The study underscores the virus’s impact on neurological pathways,
yet also highlights the body’s remarkable ability to bounce back over time.
Only about 1 in 6 people who get COVID-19, becomes serious ill and develops difficulty breathing, almost all serious consequences of COVID-19 feature pneumonia. As of 5/14/2020, globally there were over 4,437,442
coronavirus cases and around 301,937 deaths. As of 4/20/2021 the number of deaths from COVID-19 has passed 3 million worldwide,
according to John Hopkins University; there have been over 141 million confirmed cases since the pandemic began, with the US, India, and Brazil recording the most infections
and over a million deaths between them. The best way to prevent illness is to avoid being exposed to this virus.
During the coronavirus (COVID-19) disease pandemic, some U.S. healthcare officials
advised that Americans should not be walking around with masks in public because they can increase their risk of getting coronavirus
by wearing a mask if they are not a health care provider. There is no evidence for the claim that masks increase users’ risk of catching the coronavirus. The CDC’s written
guidance does not suggest that wearing a mask could increase
the risk of catching the virus. A number of Asian countries, such as Japan, South Korea, Taiwan, Hong Kong, Singapore, and Vietnam, where mask use is mandatory, have reported lower levels of
COVID-19 infection than the U.S. had. The reasons have emerged to doubt the wisdom of the guidance, and as a result, after there were over 242,180 coronavirus cases
and 5,850+ deaths in the U.S., on April 2, 2020 the CDC revised its guidance that officially advises people to wear masks in public to prevent
catching the coronavirus (COVID-19).
A new mysterious, pneumonia-like virus that originated in China in December 2019 spreads through close person-to-person contact. Each infected person seems
to spread the virus to about two others, through coughing or sneezing or by leaving germs on a surface that is touched by non-infected people who touch their faces. Coronaviruses range from the common cold to more-severe diseases such as SARS
and Middle East respiratory syndrome, or MERS. Some coronaviruses, including this new COVID-19, can cause severe symptoms and illnesses, including pneumonia. New COVID-19 illness, patient experienced a range of symptoms including fever
(95%), cough (dried: 67.7% or wet: 33.3%), headache (13.6%), fatigue (less than 10%), sore throat (13.9%), nausea (less than 3%), vomiting (less than 3%), diarrhea (less than 3%) and runny nose (less than 5%). It seems to start with a fever,
followed by a dry cough and then, after a week, leads to shortness of breath (18.6%). In more severe cases, infection can cause pneumonia, severe acute respiratory syndrome, kidney failure and even death.
Most humans fall into one of four blood groups, A, B, AB or O, and the
most common blood groups are O and A. A recent study showed that people with blood type O may be less vulnerable to Covid-19 and have
a reduced likelihood of getting severely ill, and people with blood types A, B, or AB may be more likely to be infected with COVID-19 than people with blood type O. The New
England Journal of Medicine in June, found genetic data in some Covid-19 patients and healthy people suggesting that those with Type A blood had a higher risk of becoming infected, and those with type O blood were at a lower risk. People with
blood groups A may be more likely to require mechanical ventilation, and appear to exhibit greater COVID-19
disease severity than people with blood groups O or B.
SARS (Severe Acute Respiratory Syndrome)/SARS coronavirus (SARS-CoV) virus identified in 2003 is thought to be an animal virus from an as-yet-uncertain animal
reservoir, perhaps bats, that spread to other animals (civet cats) and first infected humans in the Guangdong province of southern China in 2002. Symptoms are influenza-like and include fever, malaise, myalgia, headache, diarrhea, and shivering
(rigors). This Epidemic of SARS affected 26 countries and resulted in infecting more than 8,000 people and killing nearly 800 in 2003 during the eight-month Outbreak. Transmission of SARS-CoV is primarily from person to person. It appears to have
occurred mainly during the second week of illness, which corresponds to the peak of virus excretion in respiratory secretions and stool, and when cases with severe disease start to deteriorate clinically.
Around 60 million people died by the Spanish flu of 1918-’19; as many as
16 million people may have died in India alone.
The Asian flu (H2N2) pandemic of 1957-’58 killed 69,800 people in the US and two million worldwide. Another avian strain
(H3N2), known as the Hong Kong flu, killed 33,800 people in the US and 700,000 worldwide in 1968-’69.
Avian influenza (AI), commonly called bird flu, is an infectious viral disease of birds. Most avian influenza viruses do not infect humans; however some,
such as H5N1, have caused serious infections in people.
About 300 people around the world were infected by that strain of avian flu (H5N1, also SARS) in 2003 and more than half of them died.
As of July 6, 2009, Novel influenza A (H1N1) has infected 94,512 people
and killed 429 in 84 countries, of which, there were 33,902 cases, 170 deaths in the U.S. There are approximately 226,000 people are hospitalized each year due to
seasonal influenza and 36,000 died in the U.S. As many as 80 million Americans have been infected with H1N1 swine flu, up to 16,000 have been killed and more than 360,000 hospitalized
in the U.S. as of 1/15/2010.
The 1918 influenza pandemic was a cataclysmic event, claiming 675,000 American lives and an estimated 50 million worldwide, wiping out roughly 2% of the global population in just over a year. Fast forward to today, and while seasonal flu
is far less deadly, it still poses a serious public health challenge. In the 2024–2025 flu season, the U.S. has already seen at least 21,000 deaths, alongside 37 million illnesses and 480,000 hospitalizations—making it one of the most severe
seasons in recent years. Globally, flu activity remains variable, with elevated transmission in parts of Asia, Oceania, and South America2. Though vaccines and antivirals have dramatically reduced mortality compared to a century ago, the flu
continues to evolve, reminding us that even familiar viruses can still pack a punch.
In 2012, HIV/AIDS claimed the lives of 8,165 African Americans, compared to 5,426 white Americans and 2,586 Latinos—a grim reflection of racial disparities in healthcare.
Fast forward to 2023, and those disparities remain deeply entrenched. African Americans continue to face the highest HIV-related death rate in the country, at approximately 18 per 100,000—far surpassing other racial and ethnic groups.
While precise death counts by race aren’t publicly detailed for 2023, this rate points to the ongoing loss of thousands of Black lives each year, even in an era of medical breakthroughs and effective treatments. The contrast with lower
death rates among white and Latino populations underscores a troubling reality: HIV/AIDS is not just a biomedical issue, but a mirror of systemic inequality, shaped by barriers to care, persistent stigma, and deep-rooted social and economic
divides.
As of 2023, approximately 1.2 million people in the United States are living with HIV—similar to the total in 2011—but the racial breakdown continues to reflect deep disparities. Black/African Americans and Hispanic/Latino individuals now
account for over 70% of new HIV infections, despite representing a smaller share of the overall population. While exact prevalence numbers by race for 2023 or 2024 aren't fully published, the trend remains clear: African Americans still make up
a disproportionately large portion of those affected, likely close to or exceeding the 41% seen in 2011, with white Americans representing a smaller share than before. This shift underscores the ongoing impact of social and structural
barriers—like limited access to healthcare, stigma, and economic inequality—that continue to shape who gets diagnosed, who receives care, and who survives.
In 2011, around 1.2 million people living with HIV/AIDS in the U.S.; of which 491,110 were African Americans (41%) and 408,000 were whites (34%).
HIV/AIDS continues to carve out deep disparities in the U.S., with gay and bisexual men—particularly Black and Latino men—experiencing the fastest-growing rates of infection. In 2023, men accounted for over 80% of new diagnoses, with
male-to-male sexual contact responsible for 66% of transmissions. Black and Hispanic individuals each made up more than a third of new cases, while white Americans represented a smaller share. Women comprised about 20% of new diagnoses,
and injection drug use contributed to roughly 7–10%. These numbers reveal more than just transmission patterns—they expose the fault lines of systemic inequality, where access to care, education, and prevention remains uneven across communities.
Rates of HIV/AIDS are growing fastest among gays,
bisexual and black men; as per the CDC, the percentage of HIV/AIDS patients in the U.S. are: 76% Male, 44% Black,
33% White, 24% Female, 19% Hispanic; 53% Male-to-Male Sex, 27% Male-to-Female Sex, and 15% Injection Drug Users.
For the years after HIV/AIDS was first identified in 1984, patients survived an average of
only 18 months; now most AIDS patients do not die since the treatment is more advanced in the U.S.; for example, in 2004 it took the average patient nearly three years of daily pill popping to reach undetectable virus levels; in 2013
it only took about three months; as of today, 94% of HIV/AIDS-positive people in the city are aware of their disease, compared with 84% nationwide.
In the U.S., over 1.1 million people live with HIV/AIDS, yet the journey from diagnosis to treatment remains fragmented. According to AIDS.gov, only 84% have been diagnosed, meaning thousands remain unaware of their status. Of those diagnosed,
just 37% receive regular medical care, and only 33% are on antiretroviral therapy (ART)—the cornerstone of managing the disease and preventing transmission. These numbers reveal a troubling gap in the HIV care continuum, where access, engagement,
and adherence fall short despite the availability of effective treatment. It's a stark reminder that defeating HIV isn't just about medical breakthroughs—it's about ensuring those breakthroughs reach the people who need them most.
In the United States, over 1.2 million people live with HIV, yet the path from diagnosis to treatment remains fractured—nearly 13% are unaware of their status, and among those who are diagnosed, many still aren’t receiving consistent care
or life-saving antiretroviral therapy. This disconnect persists despite the availability of effective tools to manage and prevent the disease. Encouragingly, new infections have declined to around 31,800 annually, a shift driven by broader
testing, improved access to treatment, and the growing use of preventive measures like PrEP. Still, the epidemic continues to expose deep-rooted disparities, especially among marginalized communities, making HIV not just a medical challenge
but a reflection of systemic inequality.
The first recognized case of HIV/AIDS in the U.S. emerged in 1981, and since then, the virus has claimed over 650,000 American lives by 2014. At its most devastating peak, AIDS-related deaths soared to around 50,000 annually, turning the
epidemic into a national crisis. Today, the landscape has shifted dramatically—annual deaths have dropped to approximately 15,000, thanks to advances in antiretroviral therapy, increased awareness, and better access to care. Yet, the virus
continues to disproportionately affect marginalized communities, and the fight is far from over. HIV/AIDS may no longer dominate headlines, but its legacy—and its ongoing impact—remain deeply woven into the fabric of public health.
Acquired Immune Deficiency Syndrome or Acquired Immunodeficiency Syndrome (AIDS) is a disease of the human immune system caused by the human immunodeficiency virus (HIV).
Scientists identified a type of chimpanzee in West Africa as the source of HIV infection in humans. Although treatments for HIV/AIDS can slow the course of the disease, there is no cure for HIV infection.
The global impact of HIV/AIDS has been staggering, and recent data shows just how much the landscape has evolved. As of 2024, approximately 40.8 million people are living with HIV worldwide—a significant increase from earlier estimates.
Since the start of the epidemic in 1981, around 91.4 million people have been infected, and 44.1 million have died from AIDS-related illnesses. While annual new infections have dropped to 1.3 million and deaths to 630,000, thanks to expanded
access to antiretroviral therapy, the numbers still reflect a persistent global health challenge. Progress has been made, but the fight is far from over.
Being diagnosed with HIV does not mean a person will also be diagnosed with AIDS, which is the late stage of HIV infection, when a person’s immune system is
severely damaged and has difficulty fighting diseases and certain cancers. The early symptoms and signs of AIDS include night sweats, prolonged fevers, severe weight loss, persistent diarrhea, skin rash, persistent cough, and shortness of breath.
HIV is spread primarily by having unprotected sex with someone who has HIV; having multiple sex partners; sharing needles, syringes, rinse water, or other
equipment used to prepare illicit drugs for injection; being born to an infected mother, being “stuck” with an HIV-contaminated needle; receiving blood transfusions, blood products, or organ/tissue transplants that
are contaminated with HIV; eating food that has been pre-chewed by an HIV-infected person; being bitten/deeply kissed by a person with HIV; or tattooing or body piercing present a potential risk of HIV transmission.
Zika virus, a stealthy tropical threat, spreads through mosquito bites—primarily from Aedes aegypti and Aedes albopictus—as well as through infected blood and sexual contact. While most adults experience mild symptoms like fever, rash,
joint pain, and red eyes, the virus becomes far more sinister during pregnancy. Infected mothers can pass Zika to their unborn children, leading to congenital Zika syndrome, which includes devastating birth defects such as microcephaly
(a smaller-than-normal head), impaired brain development, vision and hearing problems, and even seizures. Not every exposed baby is affected, but the risk is highest when infection occurs early in pregnancy. Though global outbreaks have
waned since the 2015–2016 epidemic, Zika continues to simmer in parts of the Americas, Asia, and Africa, reminding the world that even a tiny mosquito can unleash profound consequences.
Ebola, a viral disease, is not spread through the air, food, water or indirect contact with an infected person; it is transmitted only through
direct contact with the bodily fluids, such as blood, diarrhea and vomit. Ebola's symptoms include fever, severe headache, muscle and stomach pain, weakness, diarrhea, vomiting and unexplained bleeding and bruising; about 50% of people infected
with Ebola died.
Ebola virus disease (EVD), once known as Ebola haemorrhagic fever, is a terrifyingly lethal illness that first erupted in 1976 in remote Central African villages, leaving a trail of devastation in its wake. Thought to originate from fruit bats,
the virus jumps to humans through contact with infected wildlife and then spreads rapidly via direct human-to-human transmission—especially through blood, bodily fluids, and contaminated surfaces. The 2014–2016 West Africa outbreak catapulted Ebola
into global consciousness, infecting over 28,000 people and killing more than 11,000, making it the deadliest episode in the virus’s history. While vaccines and treatments now exist for the Zaire strain, other variants remain untamed, and sporadic
outbreaks continue to flare across Africa, demanding swift containment and reminding the world that nature’s most dangerous pathogens often emerge from the shadows.
Ebola virus disease (EVD), which is a severe, often fatal illness in humans, outbreaks have a case fatality rate of up to 90%. EVD outbreaks occur primarily
in remote villages in Central and West Africa, near tropical rainforests. The virus is transmitted to people from wild animals and spreads in the human population through human-to-human transmission.
The Spanish flu outbreak in Shiraz, Iran, from October 29, 1918 and continued in multiple waves until 1920 was a devastating historical world event. Within three years, the population of Shiraz dropped from about 50,000 to around 20,000-25,000,
with the disease killing nearly half of the city's population. A lasting reminder of the tragedy is the Javan Abad Cemetery, where many victims were buried. The epidemic was exacerbated by World War I, British colonial presence, famine,
and malnutrition, which contributed to the city's devastation.
Between 1347 and 1351, the Black Death tore through Europe like a scythe through wheat, claiming an estimated 25 to 50 million lives—nearly a third of the continent’s population. The aftermath was seismic: villages vanished, cities emptied,
and the labor force collapsed, giving surviving peasants unexpected leverage and shaking the foundations of feudalism. Religious fervor surged as people searched for meaning in the chaos, while fear and desperation fueled persecution and paranoia.
Yet from this darkness emerged transformation—medicine began inching toward science, and the cultural shockwaves helped pave the way for the Renaissance. It wasn’t just a plague; it was a brutal reset button for medieval Europe.
The Black Death stands as the most devastating pandemic in recorded history, a grim specter that swept across Europe, Asia, and North Africa between 1346 and 1353, leaving a trail of unimaginable loss. Caused by the bacterium Yersinia pestis,
likely transmitted by fleas on rats and possibly through airborne droplets, the plague decimated populations with terrifying speed. Estimates of the death toll range from 75 to 200 million, with 25 million in Europe alone, wiping out up to 60% of
the continent’s population. Entire towns vanished, economies collapsed, and the social order was upended. The psychological and cultural impact was equally profound—fueling religious upheaval, superstition, and a shift in labor dynamics that would
echo for centuries. It wasn’t just a health crisis; it was a turning point in human history.
Throughout history, infectious diseases have been humanity’s most lethal adversaries, with tuberculosis likely claiming over a billion lives—more than any other single disease. Smallpox followed closely, ravaging populations with an
estimated 300 to 500 million deaths in just the 20th century before its eradication in 1980. The plague, infamous for the Black Death, wiped out tens of millions in medieval Europe, while malaria has quietly stalked civilizations for
millennia, still killing hundreds of thousands annually. Influenza, too, has left its mark, with the 1918 pandemic alone responsible for up to 100 million deaths. As medical advances curbed these ancient scourges, chronic conditions
like heart disease and cancer rose to dominate the modern mortality charts, reshaping the global health landscape.
