24-Hour Crisis Hotline: (877)SAFEGBC or (877)723-3422 Mental Health & Substance Abuse Issues

6502 Nursery Drive, Suite 100
Victoria, TX 77904
(361)575-0611
(800)421-8825
Fax: (361)578-5500

Medical Disorders
Resources
Basic InformationLookupsLatest News
Multiple Surgeries for Cleft Lip, Palate Won't Cause Major Psychological DamageHIV May Not Worsen COVID-19 OutlookU.S. Coronavirus Hospitalizations Spiking in South, WestAHA News: To Everything There Is a Season, Including Heart DiseaseAsthma, Allergies Plus Pandemic May Pose 4th of July ChallengesStroke Appears 8 Times More Likely With COVID Than With FluCOVID-19 Death Risk Twice as High in New York City as Some CountriesFireworks Are Bad News for Your LungsScientists Find Source of COVID ClotsNew U.S. Coronavirus Cases Top 50,000 as More States Slow Reopening PlansNumbers of Non-COVID-19 Deaths Up During PandemicNo Good Evidence on Accuracy of Coronavirus Antibody Tests: StudyAHA News: COVID-19 Pandemic Brings New Concerns About Excessive DrinkingMuscle Relaxants for Back Pain Are Soaring: Are They Safe?Trauma of Racism Fuels High Blood Pressure Among Black Americans: StudyCOVID-19 Blood Test Might Predict Who Will Need a VentilatorWhat's the Best DIY Face Mask Against COVID-19?Deep Brain Stimulation May Slow Parkinson's, Study FindsU.S. Could See 100,000 New Cases of COVID-19 Each Day, Fauci SaysGlobally, COVID-19 Cases May Stretch Far Beyond Official Numbers: StudyFBI: Beware of Scammers Selling Fake COVID-19 Antibody TestsAHA News: Sadness and Isolation of Pandemic Can Make Coping With Grief HarderVaping-Related Lung Injuries Still Happening -- And May Look Like COVID-19Most With Coronavirus Not Sure How They Caught It: CDCDon't Get Sick While Swimming This SummerAmid Pandemic, Too Many Americans Are Hesitating to Call 911Mask Up! Don't Let Down Your Guard Against COVID-19Wildfire Smoke Causes Rapid Damage to Your Health: StudyCOVID Drug Remdesivir Could Cost Up to $3,120 Per Patient, Maker SaysIntestinal Illness Spurs Recall of Bagged Salads Sold at Walmart, AldiCOVID Threatens the 3 out of 4 Americans Who Can't Work From HomeHispanic Americans Being Hit Hard By COVID-19Global Coronavirus Cases Pass 10 Million as U.S. Struggles With Surge in InfectionsStarted Early, Drug Combo Eases Fatigue of Rheumatoid Arthritis: StudyIs 'Pooled' Coronavirus Testing the Next Step for America?U.S. Coronavirus Task Force Warns of Rising Case Numbers, Especially Among YoungWho's at Highest Risk From COVID-19? CDC Updates Its ListStroke, Confusion: COVID-19 Often Impacts the Brain, Study ShowsPromising Results Mean Coronavirus Vaccine Trial Could Start by AugustWhen Can Sports Fans Safely Fill Stadiums Again?Coronavirus Baby Boom? Survey Says Maybe NotCOVID-19 Typically Mild for Babies: StudyU.S. Reports Record Rise in New Coronavirus CasesAHA News: COVID-19 Highlights Long-Term Inequities in Some CommunitiesHow the Saharan Dust Plume Could Make Your Allergies WorseAmid Pandemic, Fears That Older Americans Are Feeling 'Expendable''The Lockdowns Worked,' Experts Say, But Did America Reopen Too Soon?Asymptomatic Coronavirus Carriers Can Shed Virus on Surfaces: StudyVaccine Might Guard Against Bacteria That Cause Diarrhea in KidsOne-Time Treatment Eases Parkinson's -- in Mice
Questions and AnswersLinks
Related Topics

Diabetes

Study Suggests COVID-19 Might Follow Seasonal Pattern

HealthDay News
by By Dennis Thompson
HealthDay Reporter
Updated: Mar 19th 2020

new article illustration

THURSDAY, March 19, 2020 (HealthDay News) -- The novel coronavirus appears to be seasonal in nature, with major outbreaks occurring mainly in regions that match a specific set of climate conditions, a new study argues.

All areas experiencing significant outbreaks of COVID-19 fall within a northern corridor that has an average temperature of 41 to 52 degrees Fahrenheit and an average humidity of 47% to 79%, according to virology researchers.

These affected regions -- China, South Korea, Japan, Iran, Northern Italy, Seattle and Northern California -- all fall within a band between 30 to 50 degrees Northern latitude. There's been a lack of significant spread of COVID-19 into countries farther South.

"To us, this suggests temperature and also low absolute and specific humidity could hold a key role in transmission," said lead researcher Dr. Mohammad Sajadi, an associate professor of medicine with the Institute of Human Virology at the University of Maryland School of Medicine, in Baltimore.

"Putting all this together, we think the distribution of significant community outbreaks along restricted latitude, temperature and humidity are consistent with the behavior of a seasonal respiratory virus," Sajadi continued.

This doesn't mean that COVID-19 infection rates can be expected to fall with the coming of summer, however.

Infectious disease experts note that the novel coronavirus has proven particularly infectious, given that humans have no established immunity against it.

The coronavirus has an estimated transmission rate of 2.5 or higher, said Elizabeth Halloran, a professor of biostatistics at the University of Washington School of Public Health, in Seattle. That means every two people infected with the virus will likely spread it to a total five more people.

A virus stops being contagious when its transmission rate drops below 1, meaning that a person infected with it is not likely to spread it to another human being.

"It's going to be difficult, even if it does go down somewhat seasonally in the summer, to bring that down necessarily below 1," Halloran said. "We're looking at a very contagious infection."

For this study, virologists analyzed major outbreaks of COVID-19 and tracked the specific weather conditions in those regions.

The investigators found that in cities where the coronavirus is spreading within a community -- Wuhan, Milan and Tokyo -- temperatures did not drop below the freezing mark.

Lab studies also showed that a temperature of 39 degrees Fahrenheit and a humidity level of 20% to 80% is most conducive to the virus' survival.

"Based on what we have documented so far, it appears that the virus has a harder time spreading between people in warmer, tropical climates," Sajadi said.

But Sajadi and his colleagues warned that risk of community spread could increase in more northern areas like the Mid-Atlantic states and New England as spring blooms.

"We have a testable hypothesis that requires more research to confirm," Sajadi said. "If we do confirm this with further studies, it indicates that we may want to use the data for more targeted health system preparation, surveillance and containment efforts."

No one's really sure why season is a factor in the spread of viruses like influenza and coronavirus, experts said. It's not been established whether viruses can't survive in warmer weather, or if warmer climes somehow interfere with their ability to spread between people.

Further, each virus responds to weather in its own way, noted Dr. Martin Hirsch, a professor of infectious diseases and immunology at the Harvard T.H. Chan School of Public Health, in Boston.

"SARS [severe acute respiratory syndrome] appeared in winter and was gone by June. Others like MERS [Middle East respiratory syndrome] certainly persist on the Arabian peninsula, however, which is pretty hot," Hirsch noted.

This sort of predictive modeling "will be very important to ongoing efforts to understand novel coronavirus and mitigate its effects," said Dr. Michael Grosso, chief medical officer at Huntington Hospital in New York. "Needless to say, it would be reassuring to know that virus activity will wane with warmer weather."

But public health experts expect more will be needed than a change in season to stop the spread of COVID-19.

"Environmental conditions are one of many things that play a role within disease transmission as it is," said Nicholas DeFelice, an assistant professor of environmental medicine and public health with the Icahn School of Medicine at Mount Sinai in New York City. "It's hard to say this is the driver of it, when most likely everybody's susceptible to this new virus and that's what's driving these outbreaks. If people are susceptible, the virus can still transmit even under less-than-ideal circumstances."

Sajadi agrees.

"As the entire population probably has no previous immunity to this novel virus, it may not initially act like what we think as a seasonal respiratory virus. Also, keep in mind that being in a low-risk area does not necessarily mean that a significant outbreak will not happen there," Sajadi said.

"Public health measures may play the strongest predictive role in determining whether this virus spreads widely in the U.S.," Sajadi continued. "That is why implementation of social distancing is just as crucial in Miami as it is in New York, despite the differences in temperature."

The new study was published online on the open-data site SSRN.

More information

The U.S. Centers for Disease Control and Prevention has more about COVID-19.