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.
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.
In the U.S. around 80% of the population have received at least one dose, 68% got fully vaccinated, and 34% received a booster dose; however, as of 2/2023 the COVID pandemic is still
killing more than 450 people per day — four times as many as die in auto accidents.
On average, in the first few months of 2023, about 450 people in the U.S. have been dying each day of COVID-19, in 2021 roughly 3,200 Americans died each day when the Omicron variant was ripping through the country; however, the daily average of COVID-19 deaths was higher than it was in 12/2022, when roughly 250 Americans were losing their lives each day to the virus.
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.
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.
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 flu (Influenza Epidemic) pandemic killed 675,000 Americans and 50 million worldwide — some 2 percent of the world’s population at the time; the current state of flu deaths have an estimated 36,000 annually.
In 2012, 8,165 African Americans died because of HIV/AIDS; among whites and Latino people, 5,426 and 2,586 died, respectively.
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%).
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.
As per AIDS.gov, there were over 1.1 million Americans live with HIV/AIDS, but only 84% have been diagnosed, 37% have received
regular medical care, and 33% take anti-HIV/AIDS drugs.
The first HIV/AIDS case was reported in the U.S. in 1984, as of 2014 the disease has killed over 650,000 Americans; and at its peak, there were around 50,000
deaths from the AIDS virus per year; now the number is about 15,000.
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.
There are around 33.4 million people worldwide living with HIV/AIDS, with 2.7 million new HIV infections per year and 2.0 million annual deaths due to AIDS. Around 60 million people have been infected worldwide since the start of the pandemic in 1981, with some 25 million deaths.
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.
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), formerly known as Ebola haemorrhagic fever, is a severe, often fatal illness in humans. The virus is transmitted to people from wild animals and spreads in the human population through human-to-human transmission. The first EVD outbreaks occurred in remote villages in Central Africa.
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.
Black Death (1347-1351) wiped out large portions of the population, this plague killed an estimated 25-50 million people, wiping out about one-third of Europe's population, and leading to severe labor shortages and shifts in social structures.
