Global Statistics

All countries
Updated on September 25, 2022 6:41 pm
All countries
Updated on September 25, 2022 6:41 pm
All countries
Updated on September 25, 2022 6:41 pm

Global Statistics

All countries
Updated on September 25, 2022 6:41 pm
All countries
Updated on September 25, 2022 6:41 pm
All countries
Updated on September 25, 2022 6:41 pm
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How Many Covid Viruses Are There

Number Of Virions Within An Average Infected Person And Within The Entire Infected Population

How Many Asymptomatic Cases Of COVID-19 Are There?

We estimated the number of virions in an average infected person as the arithmetic average of the distribution of total viral load across individuals. We assumed the viral loads are distributed log-normally. We assumed the coefficient of variation of the distribution is similar to that of the distribution of the peak viral load found in ref. . The number of virions within currently infected humans was then estimated by multiplying this arithmetic average by the number of humans near peak infection. The number of humans near peak infection was chosen to represent the typical number of daily new cases reported in online tracking websites multiplied by 1 d to 3 d to account for the characteristic time an infected individual spends at near-peak viral load. Similarly, the total number of virions produced over the pandemic was estimated using probable scenarios for the total number of cases multiplied by the arithmetic average of the total production of virions over a single infection . The total mass of virions was then derived by multiplying with the average mass of a single virion. See SI Appendix for uncertainty estimation.

Number And Fraction Of Infected Cells

The total number of infected cells was estimated by dividing the peak number of virions within an infected human by the instantaneous number of virions residing in a cell. The instantaneous number of virions in an infected cell was estimated by two methods: 1) using the total yield of virions from an infected cell and 2) using an estimate of the density of viral particles within infected cells. In the first method, we start with the per-cell viral yield , and convert it into an instantaneous number of virions using a conversion factor of 3 to 30. This conversion factor equals the ratio of total production of virions to the peak viral load, which we derive in the section and SI Appendix. In the second method, estimates for the density of viral particles within cells were derived by two independent viewers counting viral particles in TEM images from the literature . Counts were converted to densities by dividing the total particle counts by the volume of the slice captured by the image, which was estimated as the area covered by the image multiplied by the diameter of a virion. The fraction of susceptible cells that are infected with SARS-CoV-2 was calculated by comparison to literature values for the number of cells in the airway system as detailed in the section .

What Is The Incubation Period For Covid

Symptoms show up in people within two to 14 days of exposure to the virus. A person infected with the coronavirus is contagious to others for up to two days before symptoms appear, and they remain contagious to others for 10 to 20 days, depending upon their immune system and the severity of their illness.

What have you learned about coronavirus in the last six months?

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Middle East Respiratory Syndrome

In September 2012, a new type of coronavirus was identified, initially called Novel Coronavirus 2012, and now officially named Middle East respiratory syndrome coronavirus . The World Health Organization issued a global alert soon after. The WHO update on 28 September 2012 said the virus did not seem to pass easily from person to person. However, on 12 May 2013, a case of human-to-human transmission in France was confirmed by the French Ministry of Social Affairs and Health. In addition, cases of human-to-human transmission were reported by the Ministry of Health in Tunisia. Two confirmed cases involved people who seemed to have caught the disease from their late father, who became ill after a visit to Qatar and Saudi Arabia. Despite this, it appears the virus had trouble spreading from human to human, as most individuals who are infected do not transmit the virus. By 30 October 2013, there were 124 cases and 52 deaths in Saudi Arabia.

After the Dutch Erasmus Medical Centre sequenced the virus, the virus was given a new name, Human CoronavirusErasmus Medical Centre . The final name for the virus is Middle East respiratory syndrome coronavirus . The only U.S. cases were recorded in May 2014.

I Recently Spent Time With Someone Who Tested Positive For Covid

Coronavirus (Covid

Yes, you do. In July 2021, the CDC recommended that anyone who is fully vaccinated and comes into contact with someone who has, or is suspected of having, COVID-19 should get tested three to five days after exposure. In addition, you should wear a mask in public indoor settings for 14 days or until you receive a negative test result. If you are vaccinated, you do not need to quarantine, but you should isolate if you develop symptoms or receive a positive test result.

Previously, the CDC had said that someone who was fully vaccinated only needed to get tested after exposure if they were experiencing symptoms. The change follows new evidence regarding the Delta variant, which shows that people who are vaccinated and then get infected can spread the virus to others, perhaps to the same extent as those who are unvaccinated.

If you are not fully vaccinated, a 14-day quarantine remains the best way to avoid spreading the virus to others after you’ve been exposed to someone with COVID-19. According to CDC guidelines, you may discontinue quarantine after a minimum of 10 days if you do not have any symptoms, or after a minimum of seven days if you have a negative COVID test within 48 hours of when you plan to end quarantine.

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How Do Mutations Happen

When a virus infects a host cell, its genetic material must be copied so that it can be put into new viruses. These new viruses are eventually released from the host cell and can go on to infect new cells.

Viruses use an enzyme called a polymerase to copy their genetic material.

However, polymerases arent perfect, and they can make mistakes. These mistakes can result in a mutation. Many times, a mutation either does nothing or is harmful to a virus. But in some cases, it may help the virus.

When mutations are harmful, they can affect a virus ability to infect or multiply within a host cell. Because they dont function well, new viruses that contain a harmful mutation often dont survive.

However, sometimes a mutation gives a newly produced virus an advantage. Perhaps it allows the virus to bind more tightly to a host cell or helps it escape the immune system.

When this happens, these mutant, or variant, viruses can become more common within a population. This is what were currently seeing with the new variant strains of SARS-CoV-2.

Are There Different Variants Of This Coronavirus

Yes, there are different variants of this coronavirus. Like other viruses, the coronavirus that causes COVID-19 can change . In December 2020, B.1.1.7, a new variant, was identified in the United Kingdom, and since then, variants have appeared in other locations around the world, including B.1.351, first isolated in South Africa, and others. Mutations may enable the coronavirus to spread faster from person to person, and may cause more severe disease. More infections can result in more people getting very sick and also create more opportunity for the virus to develop further mutations. Read more about coronavirus variants.

Coronavirus: What do I do if I Feel Sick?

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Symptoms Spread And Other Essential Information

What is coronavirus and how does it spread? What is COVID-19 and what are the symptoms? How long does coronavirus live on different surfaces? Take a moment to reacquaint yourself with basic information about this virus and the disease it causes.

Click here to read more about COVID-19 symptoms, spread, and other basic information.

How Might Variants Effect The Timeline For Herd Immunity

Coronavirus v Influenza: How do the two viruses compare? – BBC News

The fact that these variants exist and are spreading doesn’t automatically lengthen the path to herd immunity, Vermund said. But it does make getting vaccinated against COVID-19 and adhering to safety practices that much more influential in the timeline for getting back to normal.

“If we can get broader adherence to prevention messages and drive down rates, even if we have these new strains circulating, we may be able to control the virus until we can get everybody vaccinated,” he said. “If we just flagrantly flaunt the prevention messages, then, sure, the new strains, if they’re more infectious, will affect more people and make things bad again.”

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What You Need To Know About Variants

The Omicron varianthas been detected in the United States. CDC and its public health partners are closely monitoring the emergence of this variant of concern. Updates in the CDC Newsroom.

Information about Variants: Viruses constantly change through mutation and sometimes these mutations result in a new variant of the virus. Some variants emerge and disappear while others persist. New variants will continue to emerge. CDC and other public health organizations monitor all variants of the virus that causes COVID-19 in the United States and globally.

The Delta variant causes more infections and spreads faster than the original SARS-CoV-2 strain of the virus that cause COVID-19. Vaccines remain the best way to reduce your risk of severe illness, hospitalization, and death from COVID-19.

Estimate Of The Number Of Virions In An Infected Individual

    A schematic representation of the estimate of the number of virions in an infected individual. The estimate is made using the viral load measured in a gram of rhesus macaque tissue multiplied by the mass of human tissues in a reference adult person with a total body weight of 70 kg . In the digestive tract, the concentrations are close to the detection limit. We assume the number of virions is similar to the number of RNA copies.

    In addition to analyzing the state of an infected individual during peak infection, we can also estimate the total number of virions and infectious units produced over the course of an infection, as well as the rate of virion production inside a human host. To estimate the total number of virions produced during an infection, we consider the viral load curve as a function of the time since infection. The total production of virions can be estimated by the area under the viral load curve divided by the reciprocal of the viral clearance rate . Using a previously published model of exponential growth and decay , we analytically calculated the area under the curve. Dividing by estimates for the inverse of the viral clearance rate gives an estimated total production of 3 × 109 to 3 × 1012 virions, or 3 × 105 to 3 × 108 infectious units over the complete course of a characteristic infection . Thus, the ratio between the total production of virions to their peak number is in the range of 3 to 30.

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    Cases Reported Since The Start Of The Vaccination Campaign As Of July 03 2021

    Since the start of the vaccination campaign on December 14, 2020, PHAC received case-level vaccine history data for 75.5% of COVID-19 cases aged 12 years or older.

    Of these cases:

    • were unvaccinated at the time of their episode date
    • were not yet protected by the vaccine, as their episode date occurred less than 14 days after their first dose
    • were only partially vaccinated, as their episode date occurred either 14 days or more after their first dose or less than 14 days after their second dose
    • were fully vaccinated, as their episode date occurred 14 days or more after their second dose

    How Many Coronaviruses Are Found In Humans

    Important Message Re: Coronavirus Disease (COVID

    To date seven human coronaviruses have been identified . Four of them are common less high risk and typically cause only mild respiratory illnesses in healthy human adults. However, they contribute to a third of common cold infections and, in higher risk people with weak immune systems, they can cause long term, life-threatening illnesses.

    The other three are known to cause more severe illness such as shortness of breath and even death. COVID-19 illness tends to be milder than SARS and MERS but more severe than disease caused by the four common coronaviruses.

    Human coronavirus name

    Because this virus is new, no-one has any immunity to it. This means it will potentially infect very large numbers of people. And even though the number of very severe cases is low in percentage terms, a small percentage of a very large number adds up to many people with acute illness.

    It is thought that all seven human coronaviruses might have been transmitted to humans from other animals. Those causing MERS, SARS and COVID-19 probably originated from bats. It is possible that the transfer of the new COVID-1 from its original host species to humans involved another animal species, such as the pangolin, as an intermediate host.

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    What Is Different About The New Coronavirus

    The new SARS-CoV-2, is most closely related to a group of SARS-CoVs found in humans, bats, pangolins and civets.

    Even though there are many similarities between the new COVID-19 and the virus that caused the SARS epidemic, there are also differences resulting from changes in their genomes. This includes how they are passed from one individual to another, and the differing symptoms of coronaviruses. Early reports suggest that the new coronavirus is more contagious than the virus that caused SARS but less likely to cause severe disease.

    What Is The New Naming System For Covid

    The WHO recently announced a new naming system for COVID-19 variants. The new names are intended to be easier to pronounce and will remove the stigma of a variants being associated with a particular country.

    Under the new system, the variants will be named using letters of the Greek alphabet. For example:

    • Alpha is the new name for the B.1.1.7 variant, first documented in the United Kingdom.
    • Beta is the new name for the B.1.351 variant, first documented in South Africa.
    • The P.1 variant, first documented in Brazil, will now be known as Gamma.
    • The B.1.617.2 variant, first documented in India, will be called Delta.

    For a complete list of new SARS-CoV-2 variant names, .

    Scientists will likely continue referring to variants by strings of letters and numbers, which provide information about a variants lineage.

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    Where Are Cases Still High

    The number of daily cases is stable or falling in most regions.


    Asia, which was the centre of the initial outbreak that spread from Wuhan in China in early 2020, has seen cases fall in recent weeks.

    There have. however, been spikes in Japan, Malaysia and Thailand.

    In India, where the number of new daily cases has fallen recently, the official death toll is 436,000 and it has recorded 32 million cases – second only to the US.

    Latin America

    In Latin America, Brazil has recorded more than 20 million cases and nearly 580,000 deaths – the world’s second highest official death toll.

    Mexico has seen the fourth highest number of deaths in the world, with nearly 260,000, and is currently seeing another surge in cases.

    Peru now has the fifth highest toll with nearly 200,000 deaths, but the highest number of deaths by population size – more than 600 deaths for every 100,000 people.


    Several European countries have seen a rise in cases recently, driven by the Delta variant of the virus, including Russia, Germany and Greece.

    In the UK there has been a recent rise in daily cases, though the high level of vaccination has greatly reduced the number of hospitalisations and deaths.

    North America

    The US has recorded nearly 40 million cases and more than 630,000 deaths – the highest figures in the world.

    Daily case numbers in the US fell in May and June but are rising again as Delta becomes the main variant in circulation.

    Middle East



    How Many Cases Of Coronavirus Are There In Toronto

    How many people have been tested for coronavirus in Georgia?


    COVID-19 continues to be prevalent in Toronto and the rest of Ontario.

    Here are Toronto’s latest COVID-19 case numbers, based on data released by Toronto Public Health.

    In Toronto, as of Dec. 10: 301 new cases and one new death, for a total of 184,962 cases and 3,719 deaths, with 1,659 active cases and 26 people currently hospitalized in the city. Toronto Public Health releases its numbers on weekdays by 4 p.m.

    The Ontario Ministry of Health’s latest numbers, from Dec. 9 , note 1,453 new cases, 11 new deaths and 910 newly resolved cases, for a total of 629,064 confirmed cases, 10,065 deaths and 609,806 resolved cases in the province.

    Of the 1.,453 new cases, the province noted 613 are unvaccinated, 26 partially vaccinated and 718 fully vaccinated, with vaccination status unknown for 96 cases. The province releases its numbers each day at 10:30 a.m.

    In Canada, as of Dec. 9, there has been a total of 1,823,009 cases, 29,876 deaths and 1,761,838 resolved cases. Currently, there are 31,295 active cases in the country. The Government of Canada updates its numbers weekdays at 7 p.m. The first reported case of COVID-19 in Canada was in Toronto on Jan. 25, 2020. is updating this article with new numbers as they are announced. Public health agencies do not provide updates on holidays.

    To learn more about the virus, visit

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    Delta Variant From India

    This variant is believed to have first emerged in India in October 2020. It’s since spread to the U.S. and currently accounts for more than 6% of sequenced cases in the U.S., Dr. Anthony Fauci said at a recent news briefing. It also has increased transmissibility compared to other variants, according to the World Health Organization.

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