90% of Coronavirus Infections Are Asymptomatic

Analysis by Dr. Joseph Mercola Fact Checked

coronavirus asymptomatic patients

Story at-a-glance -

  • A hospital in New York City began universal screening for SARS-CoV-2, the virus that causes COVID-19, among pregnant women admitted for delivery
  • Overall, 87.9% of the women who tested positive for SARS-CoV-2 had no symptoms
  • Of 408 people tested at a homeless shelter in Boston, 36% were positive, but symptoms were uncommon among the COVID-positive individuals
  • In a pilot study, 200 participants were tested to see if they had antibodies made by their immune system to fight off COVID-19, which would suggest they’d been previously infected and may not have known it
  • In a pilot study, 32% of 200 individuals tested positive for antibodies linked to COVID-19, but only about half said they’d experienced at least one COVID-19 symptom in the past four weeks
  • A modeling study by researchers at Oxford University’s Evolutionary Ecology of Infectious Disease lab suggests up to half of the U.K. population may have already been infected

The symptoms of COVID-19 — fever, cough, shortness of breath, chills, muscle pain — are widely reported via the media and public health organizations. Less publicized, however, is the fact that a sizable number of people with COVID-19 do not experience symptoms at all.

Even the U.S. Centers for Disease Control and Prevention (CDC), in their about-face regarding the usage of masks to slow the spread of COVID-19, stated, "We now know from recent studies that a significant portion of individuals with coronavirus lack symptoms ("asymptomatic") …"1

One of those studies found that in a family of three who had all tested positive, only one — a 35-year-old man — had symptoms. The other two family members, a 33-year-old woman and 3-year-old boy, were asymptomatic.2

Since widespread testing hasn't been done in the U.S., and most of those who have been tested had symptoms, it's largely unknown how many people may have already had, and recovered from, COVID-19 but didn't know it because they didn't have symptoms.

The few studies that have been done toward this end, however, are providing revealing data showing that 87.9% of one group that tested positive had no symptoms.3

Majority of Pregnant Patients With COVID-19 Had No Symptoms

A hospital in New York City began universal screening for SARS-CoV-2, the virus that causes COVID-19, among pregnant women admitted for delivery. Between March 22, 2020, and April 4, 2020, 215 were screened on admission for symptoms of COVID-19 and tested for the virus.

Only four of the women had fever or other COVID-19 symptoms, and all four tested positive. Of the remaining women who were tested even though they had no symptoms, 13.7% — 29 — were positive. This means that, overall, 87.9% of the 33 women who tested positive for SARS-CoV-2 had no symptoms.4

Among those who tested positive without symptoms, three women (10%) developed fever before they were discharged from the hospital (within about two days). However, two of these women were treated for endomyometritis, a pregnancy complication that causes fever, while only one was presumed to have developed a fever due to COVID-19.

In one additional woman who had initially tested negative, symptoms developed after delivery and she tested positive three days after the initial test. The study authors explained:5

"Our use of universal SARS-CoV-2 testing in all pregnant patients presenting for delivery revealed that at this point in the pandemic in New York City, most of the patients who were positive for SARS-CoV-2 at delivery were asymptomatic, and more than one of eight asymptomatic patients who were admitted to the labor and delivery unit were positive for SARS-CoV-2."

Study co-author Dr. Dena Goffman, with the Columbia University Irving Medical Center, told CBS News, "If we're not checking, we really do risk missing people who are carrying the virus."6 And therein lies the point — most people aren't being tested for COVID-19, especially those without symptoms, so it's anyone's guess how much of the population may have already had it.

Click here to read moreClick here to read more

Symptoms 'Uncommon' During COVID-19 Outbreak at Shelter

Another example of COVID-19's apparent stealth came from a large homeless shelter in Boston. After a cluster of COVID-19 cases was observed there, researchers conducted symptoms assessments and testing among all guests residing at the shelter over a two-day period.7

Of 408 people tested, 147, or 36%, were positive, and although the positive individuals were more likely to be male, there were no other distinguishing characteristics. That being said, symptoms were conspicuously absent.

Cough occurred in only 7.5% of cases, shortness of breath in 1.4% and fever in 0.7%. All were "uncommon among COVID-positive individuals," the researchers noted, adding that because COVID-19 can apparently be transmitted rapidly in a homeless shelter setting without a corresponding rise in symptoms, universal testing, rather than a symptom-triggered approach to testing, may be a better strategy for identifying cases.

In Chelsea, Massachusetts, a city across the Mystic River from Boston, many cases are also occurring without symptoms. As of April 17, 2020, Chelsea had the highest rate of confirmed COVID-19 cases in Massachusetts — 32%, although the actual rate is probably higher.8

In a pilot study by physicians at Massachusetts General Hospital, 200 participants who "generally appeared healthy" were tested to see if they had antibodies made by their immune system to fight off COVID-19, which would suggest they'd been previously infected and may not have known it.

Among them, 32% tested positive for antibodies linked to COVID-19. However, only about half said they'd experienced at least one COVID-19 symptom in the past four weeks. Chelsea's city manager, Thomas Ambrosino, told the Boston Globe, "[I]t's kind of sobering that 30 percent of a random group of 200 people that are showing no symptoms are, in fact, infected."9

While studies are hinting that the majority of COVID-19 patients in some populations could be without symptoms, the CDC has also confirmed that asymptomatic COVID-19 cases exist. "One of the [pieces of] information that we have pretty much confirmed now is that a significant number of individuals that are infected actually remain asymptomatic," CDC director Dr. Robert Redfield, told NPR. "That may be as many as 25%."10

Further, as reported in a correspondence article in The Lancet, in which researchers made a case for mass testing of both symptomatic and asymptomatic health care workers:11

"The number of asymptomatic cases of COVID-19 is significant. In a study of COVID-19 symptomatic and asymptomatic infection on the Diamond Princess cruise ship, 328 of the 634 positive cases (51.7%) were asymptomatic at the time of testing. Estimated asymptomatic carriage was 17.9% … whereas China's National Health Commission recorded on April 1, 2020, that 130 (78%) of 166 positive cases were asymptomatic."

Is Half the Population Potentially Already Part of the Herd?

When the majority of people have had an infectious disease and naturally acquired long lasting natural immunity, herd immunity is said to have developed. Could it be that natural herd immunity is developing for COVID-19, with many not even realizing they've already had it?

Yes, according to a hypothetical modeling study by researchers at Oxford University's Evolutionary Ecology of Infectious Disease lab, which suggests up to half of the U.K. population may have already been infected.12

They suggested that, according to public health theory, SARS-CoV-2, assuming it elicits protective immunity, will conform to the three distinct phases that typically occur when a novel infectious agent elicits protective immunity:13

  1. An initial phase of slow accumulation of new, often undetectable, new infections
  2. A second phase of rapid growth in cases of infection, disease and death
  3. An eventual slow down of transmission due to the depletion of susceptible individuals, typically leading to the termination of the first epidemic wave

The hypothetical modeling used data on COVID-19 deaths from the U.K. and Italy, and assumed that such deaths occur only in a vulnerable fraction of the population. As reported by New York magazine, under this scenario:14

"[T]he coronavirus arrived in mid-January at the latest, and spread undetected for over a month before the first cases were confirmed. Based on a susceptibility-infected-recovery model — a commonly used estimate in epidemiology — with data from case and death reports in the U.K. and Italy, the researchers determined that the initial 'herd immunity' strategy of the U.K. government could have been sound."

That is, the U.K. initially planned to suppress the spread of COVID-19 but not completely eliminate it, allowing it to spread among younger, less vulnerable populations while protecting the elderly and immunocompromised.15 They since changed strategies, in part because of reports suggesting up to 250,000 people could die using the suppression plan, to one adopted by most other countries, involving case isolation, social distancing and widespread closures.

"I am surprised that there has been such unqualified acceptance of the Imperial model," said lead researcher Sunetra Gupta, calling for immediate large-scale antibody testing to determine what stage of the pandemic we're currently facing.16 The researchers further noted:17

"Importantly, the results we present here suggest the ongoing epidemics in the UK and Italy started at least a month before the first reported death and have already led to the accumulation of significant levels of herd immunity in both countries.

There is an inverse relationship between the proportion currently immune and the fraction of the population vulnerable to severe disease. This relationship can be used to determine how many people will require hospitalisation (and possibly die) in the coming weeks if we are able to accurately determine current levels of herd immunity."

Vaccines for Everyone — Don't Become Naturally Immune!

Biotech company Moderna began the first clinical trial for a COVID-19 vaccine in March 2020. Biotech company Inovio, which is funded by the Bill & Melinda Gates Foundation, is the second company to start testing an experimental COVID-19 vaccine in humans in the U.S.18

At least 70 COVID-19 vaccines are under development,19 each of them likely attempting to be fast-tracked to the market.20 Under normal circumstances, a vaccine may take five to 10 years to be developed, and pushing rapid progress comes with significant safety concerns.

The Bill & Melinda Gates Foundation is funding the construction of factories to produce seven vaccine candidates,21 with the winning vaccine being produced en masse, to vaccinate the world's population. Foundation chief executive Mark Suzman said, "There are 7 billion people on the planet. We are going to need to vaccinate nearly every one. There is no manufacturing capacity to do that."22

The Bill & Melinda Gates Foundation is the biggest funder of the World Health Organization (WHO), by the way, and in a Washington Times opinion piece, published March 31, 2020, Gates calls for the complete shutdown of all U.S. states and quarantining of all Americans "until the case numbers start to go down … which could take 10 weeks or more."23

While Gates can undoubtedly afford it, few working-class Americans would be able to survive without income for months on end and could face serious mental health repercussions as a result.

So Gates, a key funder of WHO, is calling for a 10-week or longer shutdown of the U.S. and the rapid building of brand-new vaccine manufacturing facilities to handle the manufacturing of billions of doses of COVID-19 vaccine — which would be rendered useless if it turns out that the majority of the population has already been exposed to the virus by going about their daily lives, and thereby acquired herd immunity naturally.