Coronavirus (COVID-19)

COVID virus image

As of late June 2024, COVID-19 (Coronavirus) variants have shifted again, and infections have increased throughout California.

With most people either not testing or testing at home, Mono County Public Health cannot accurately track case numbers like we were able to do a few years ago. What we do know is that currently severe disease causing hospitalization or death is uncommon in our area, and COVID-19 levels in Mammoth Lakes wastewater are not high.

Most people have some level of COVID-19 immunity, decreasing the risk of severe illness. But immunity fades with time, and staying up to date with COVID-19 vaccinations is still recommended.

Studies on vaccine effectiveness against new FLiRT variants are not yet available. Updated vaccines are expected in the coming months, specifically targeting 2024 COVID-19 variants.

Free COVID-19 tests are available from the Mono County Public Health Department (supplies limited).

Individuals infected with COVID-19 should isolate until fever is gone and symptoms are mild and improving. Mask-wearing is recommended in indoor public settings for 10-days after symptom onset, to avoid infecting other people.

Treatment to reduce chances of getting very sick with COVID-19 can be considered by anyone, but is most important for people at high risk. Talk to your healthcare provider if you’re not sure about your risk.

On January 9, 2024, the California Department of Public Health (CDPH) released new Coronavirus (COVID-19) isolation and exposure guidance.  This guidance is intended to support individuals returning to normal activities sooner.  The California Division of Occupational Safety and Health (Cal/OSHA) has concurrently adopted these guidelines as the rules for most California workplaces.


Mono County is continuing to track positive COVID-19 cases reported from healthcare providers and laboratories as well as self-administered home antigen tests.  Click here to report your positive test.


  1. Stay home if you have COVID-19 symptoms, until you have not had a fever for 24 hours without using fever reducing medication, AND other COVID-19 symptoms are mild and improving.  If you do not have symptoms, you should follow the recommendations below to reduce exposure to others, but you do not need to isolate.
  2. Mask when you are around other people indoors for the 10 days* after you become sick or test positive (if no symptoms) for COVID-19.  You may remove your mask sooner than 10 days if you have two sequential negative tests at least one day apart.  Day 0 is symptom onset date or positive test date.
  3. Avoid contact with people at higher-risk for severe COVID-19 for 10 days*.  Higher-risk individuals include the elderly, those who live in congregate care facilities, and those who have immunocompromising conditions that put them at higher risk for serious illness.
  4. Seek treatment.  If you have symptoms, particularly if you are at higher risk for severe COVID-19, speak with a healthcare provider as soon as you test positive as you may be eligible for antiviral medicines or other treatments.  COVID-19 antiviral medicines work best if taken as soon as possible, and within 5-7 days from when symptoms start.  Call (833) 422-4255 if you are unable to contact a healthcare provider, or use the treatment options to find one.


  • If you have new COVID-19 symptoms, test and mask right away.
  • If you do not have symptoms, and are at higher risk of severe COVID-19 infection and would benefit from treatment, you should test within 5 days.
  • If you do not have symptoms and have contact with people who are at higher risk for severe infection, you should mask indoors when around such people for 10 days.  Consider testing within 5 days after the last exposure date (Day 0) and before contact with higher-risk people.  For further details, see CDPH’S COVID-19 testing guidance.


In the workplace, employers are subject to the Cal/OSHA COVID-19 Non-Emergency Regulations,  or in some workplaces the Cal/OSHA Aerosol Transmissible Diseases (ATD) Standard and should consult those regulations for additional applicable requirements.  In certain healthcare situations or settings and other covered facilities, services and operations, surgical masks or respirators are required.

Note that this guidance relies upon people being willing to test for COVID-19 and to wear masks if they are positive in order to protect others.  Masks vary in their effectiveness, and all masks must be worn properly and consistently in order to reduce the chances of spreading COVID-19.  See the CDC’s Use and Care of Masks information.

*The potential infectious period is 2 days before the date of symptoms began or the positive test date (if no symptoms) through Day 10. (Day 0 is the symptom onset date or positive test date).

A Message from Mono County Health Office Dr. Tom Boo

The California Department of Public Health (CDPH) has quietly released updated guidance on how to reduce the spread of Coronavirus (COVID-19).  This guidance is reflected in updated California Division of Occupational Safety and Health Administration (Cal/OSHA) regulations, and establishes the current legal standard for California workplaces.

COVID-19 is less dangerous now than it has been in the past because most people have some immunity, and because good treatments are now more readily available. For many people, COVID-19 in 2024 is comparable to the common cold. However, it still poses a significant public health threat, with weekly COVID-19 deaths nationwide running around 1,600, or about 4 percent of all deaths. In California this third week of January approximately 2,300 individuals are hospitalized with COVID-19.  Most, but not all, of these people experiencing severe COVID-19 have risk factors, especially old age.

California's new approach to isolation differs from that of the U.S. Centers for Disease Control and Prevention (CDC) in dropping the 5-day minimum period to stay at home after COVID-19 onset. CDPH aims to treat COVID-19 more like other respiratory viruses and wants to reduce absenteeism in schools and the workplace while focusing on protecting higher-risk people.  It seems certain that more people will be returning to work and school with contagious COVID-19 under the new rules, relying upon masking for “source-control.”  As with all things COVID-19, the new guidance is not without controversy-there has been some criticism in the media since the guidance was released on January 9, 2024.

California is not the first state to adopt a symptom-based approach for COVID-19 isolation, and CDPH points to Oregon, which took a similar approach in May 2023. In comparing COVID-19 trends between California and Oregon after their change in isolation guidance, CDPH found no difference. The change thus appears to make sense at the population level, but the implications seem nuanced and variable for individuals and employers.

The new guidance relies heavily on masking for source control to prevent infection spread, noting that masks have to be worn consistently to protect others.  Keep in mind that all masks are not equal in preventing transmission. Well-fitting N-95 respirators with elastics around the head are the most effective and should be used when possible. KN-95 and KF-94 respirators that loop behind the ears are generally effective, although variations in manufacturing quality can be a problem. Similarly, well-fitting medical-grade procedure masks (also known as surgical masks) are recommended if a respirator is not an option, but product quality may vary. Tightly woven multilayered cloth facemasks are also among the recommended options but in general are less effective than the other choices.  CDC has useful information on masking here.  A good fit is essential with any mask, and they should have a wire nose bridge and no significant gaps around the edges.  Masking has protective value when either an infected or an exposed person is wearing one appropriately but is most effective when all parties are using them.

The role of testing is evolving. The guidance continues to rely upon people testing to diagnose COVID-19 when they have compatible symptoms (asymptomatic infection and great variability in symptoms continue to complicate efforts to reduce transmission).  But when one has been exposed to COVID-19, CDPH no longer recommends routine testing unless there are symptoms, except for people with risk factors for severe COVID-19, or people in contact with other people at high risk.

When one has COVID-19, rapid tests remain valuable in reducing risk to others, as positivity appears to correlate well with being potentially contagious.  The new state guidance states that people can remove their masks before 10-days if two rapid tests are negative, taken at least a day apart.  In addition, as Mono County Health officer, I believe it is very reasonable for people who want to be more careful to continue to use rapid testing to decide when to end isolation, even when using a mask.  Adding testing to symptom criteria for ending isolation would be most important for those who could be around people who are more vulnerable. The updated guidance asks us to avoid contact with high-risk people and settings, but it may not be possible to identify higher-risk individuals.    

Cal/OSHA's adoption of symptom-based rules sets a minimum standard, still allowing employers to take an approach more protective of workers, if appropriate. Workplace populations may include immunocompromised individuals and others who may be uncomfortable around potentially contagious colleagues with COVID-19. Employers who wish to exercise greater caution may choose to follow CDC’s guidance, which is more conservative than Cal/OSHA’s new rules, or CDPH’s more restrictive rules for healthcare workers (at least 5-days isolation with a negative COVID-19 test on day 5 or later, and use of N-95 respirator for source control).

The state guidance emphasizes staying away from higher risk people when one has COVID-19. Most obviously, those at higher risk include older people. Advanced age is the most critical risk factor for severe COVID-19, with individuals older than 75 facing significantly increased mortality rates. The older the person, the greater the chance of severe disease; according to the CDC, the risk of death is more than 300 times higher in people 85 years and older than in young adults 18-25 years old. Any congregate facility, including nursing homes, homeless shelters and jails, are considered high risk and should be avoided by people with COVID-19 until 10-days have passed, with or without masking. Residents of nursing homes and healthcare facilities are particularly vulnerable, and it should be noted that the new less restrictive isolation guidance does not apply to healthcare workers.  

Apart from age, numerous health conditions increase the risk of severe COVID-19. Risk is additive, so the more conditions one has the higher the risk. Being unvaccinated also increases the COVID-19 risk, although prior infections may provide good immune protection. Relevant information about health conditions associated with higher COVID-19 risk can be accessed here.

The updated guidance from CDPH represents a subtle shift towards more personal responsibility and situational awareness. This approach requires that persons with respiratory illness test for COVID-19 and act accordingly, determining when it is safe to end isolation without putting others at undue risk of infection.

Recommended actions based on increased transmission include:

  • Stay home if sick (when possible);
  • If you must leave home while sick, wear a mask in public;
  • Get tested if you have symptoms;
  • Stay up-to-date with COVID-19 vaccines; and,
  • Report Your Positive Test. Mono County is continuing to track positive COVID-19 cases reported from healthcare providers and laboratories as well as self-administered home antigen tests.
Additional precautions for individuals at high risk for severe illness include:
  • Stay six feet away from others;
  • Avoid poorly ventilated spaces and crowds;
  • Wash your hands often;
  • Cover coughs and sneezes;
  • Clean and disinfect high-touch surfaces; and,
  • Follow recommendations for quarantine and isolation.

Details on these additional precautions can be accessed here.

IF you do get sick and/or test positive for covid-19

Early treatment generally prevents progression to severe COVID-19, so do not delay testing. Everyone 12 years and older who tests positive for COVID-19 and has symptoms should consult with their primary care physician regarding treatment options.

If you've tested positive for COVID-19 and are unable to connect with a medical provider within 24 hours, please call (833) 686-5051 or visit SESAME to schedule a free virtual COVID-19 medical appointment.

COVID-19 medications Paxlovid and Lagevrio are currently free for anyone in Califronia, regardless of insurance or immigration status.


Free COVID-19 home tests are available for pick-up at Mono County Health Department offices in Bridgeport and Mammoth Lakes. 

✔️ Monday - Friday: Mono County Civic Center (1290 Tavern Road; Mammoth Lakes); 8am - 5pm (excluding holidays)

✔️ Thursdays: Bridgeport Public Health Office (37 Emigrant Street; Bridgeport); 10am - 2pm (excluding holidays)

When to test:

If you begin having COVID-⁠19 symptoms, including fever, sore throat, runny nose, or loss of taste or smell, or;
At least 5 days after you come into close contact with someone with COVID-⁠19, or;
When you’re going to gather with a group of people, especially those who are at risk of severe disease or may not be up to date on their COVID-⁠19 vaccines.

Free Virtual COVID-19 Test-to-Treat Services

Mono County businesses interested in obtaining free COVID-19 tests for their employees are encouraged to contact the Mono County Health Department at (760) 932-5580 (Bridgeport) or (760) 924-1830 (Mammoth Lakes).

Key Topics / Temas Importantes 

CDPH COVID-19 Outbreak Data

COVID-19 Testing Information

Datos de brotes de COVID-19

Información sobre la prueba de COVID-19

Directives / Directivos 

CDPH Case Stats / Estadisticas de Casos 

Case Stats 

Estadisticas de Casos