One of the oldest diseases still circulating in third world countries is measles.
The first recorded cases of measles were in the seventh century, and if a person is not vaccinated, the death rate is between 15 and 25 percent, according to data from the United States Centers for Infectious Disease Control and Prevention (CDC).
Because of the duration of measles, it is impossible to determine how long the disease lasts.
According to the World Health Organization, measles (airborne transmission) is the most contagious and between 92 and 95 percent of the population needs to be immunized, so the remaining five to eight percent cannot catch the disease.
Polio or polio, also a very dangerous disease, was recorded in the 18th century and most commonly affects children between the ages of three and eight.
Before vaccines appeared in the middle of the last century, the mortality rate was from two to five percent in children, from 15 to 30 percent in adults, and that percentage increased with brain complications by as much as 75 percent.
The WHO adds that the percentage needed to acquire collective immunity to polio (transmitted via the oral-fecal route) is around 80 percent.
Smallpox or smallpox is perhaps the oldest disease today, as it originated about 3,000 years ago in India.
WHO data show that, without vaccination, the mortality rate is 30 percent, and survivors often have permanent scars.
It is not known how many people died from this virus.
In order to neutralize smallpox (transmitted through air and droplets), it is necessary to immunize, according to WHO experts, 80 percent of people.
The pertussis vaccine was created in 1926, but according to the American CDC, there are currently 24.1 million cases in the world, and 160,000 people die each year.
According to data from Harvard, for whooping cough (transmitted by air and droplets), 92-94 percent of the population needs to be immune to protect the rest.
Mumps is also a very old disease first recorded in the fifth century, and the mortality rate per 10,000 population is between 1.6 and 3.8 percent, due to complications caused by inflammation of the brain.
Data from Harvard say that mumps, which is transmitted through air and droplets, requires that between 75 and 86 percent of the population be immune, and a vaccine was created in 1967.
In developed countries, the death rate from the rubella virus (airborne and droplet transmission) is between 0.05 and 0.1 percent per 1,000 cases, much lower than in third world countries, where the death rate is between three and six percent.
The virus was registered in 1815, a vaccine was created in 1967, and it’s estimated that between 83 and 85 percent of the immune system creates collective immunity, according to data from Harvard.
SARS was discovered in 2002 in China and was active until 2004, and is transmitted by air and droplets.
The WHO estimates the death rate to be around 11% when the epidemic ends, affecting four countries other than China.
8,098 people became infected and 774 died when the WHO declared an end to the epidemic in July 2003, although there were several cases the following year.
There is no vaccine yet, although the virus has mysteriously disappeared so far.
For SARS (airborne and droplet transmission), it is estimated that between 50 and 80 percent of the population must be immune to stop the spread.
As for Ebola (transmitted through bodily fluids), the most dangerous of these viruses, the mortality rate is around 50 percent.
The first case was reported in Congo in 1976, and it is estimated that more than 80 per cent of people need to be vaccinated for herd immunity, but that figure is uncertain, as it is uncertain how long it will take to protect against Ebola. The US FDA (Food and Drug Administration) approved the first vaccine in 2019.
Apart from Ebola, the major threat to humanity is Kovid-19’s “cousin” – MERS.
MERS belongs to the coronavirus group, and the first cases were recorded in 2012 in Jeddah, Saudi Arabia, and the death rate was between 34 and 35 percent in January 2020, according to WHO.
There were 858 deaths out of 2,519, and MERS is also called humpback camel disease, which transmits the virus to humans.
It is not entirely certain whether it is transmitted only by droplets or if there is some other means of person-to-person transmission.
When it comes to COVID-19, one of the coronavirus viruses, which is transmitted by air and droplets, scientists still can’t agree on the percentage of immunity needed for herd immunity, especially since it’s a virus that returns after a while. months and not all was known about him.
More than 1.5 million people have died from covida 19 so far, nearly 70 million cases have been infected in the world, and to stop the spread, and scientists don’t agree, between 60 and 80 percent of people need to have immunity.
Collective immunity or “herd immunity” develops when most individuals in a community develop immunity to disease that prevents disease transmission, so that the entire community is protected, not just those who are immune to a particular disease.
To develop collective immunity, first of all the infection needs to spread, for people to be vaccinated, so there are different percentages of various diseases that need to occur in order to develop “herd immunity.”