Is a Sinus Infection Contagious? What Doctors Say

The Short Answer

It depends on the cause. Viral sinus infections, which account for the vast majority of cases, are contagious because the underlying virus can spread from person to person. However, the sinus infection itself does not transmit directly — what spreads is the cold or flu virus that triggered it. Bacterial and fungal sinus infections are not contagious.

Understanding the difference matters for protecting your family, planning your return to work, and knowing when you need medical treatment versus rest and home-based sinus pressure relief.

How Sinus Infections Develop

Your sinuses are four pairs of air-filled cavities behind your forehead, cheeks, nose bridge, and eyes. They are lined with a thin mucous membrane that traps bacteria, dust, and allergens. When this membrane becomes inflamed — a condition called sinusitis — mucus cannot drain properly, creating a warm, moist environment where pathogens thrive.

Most sinus infections begin as a common cold. The rhinovirus or influenza virus inflames the nasal passages, blocking the sinus drainage pathways called ostia. Within a few days, the trapped mucus can become secondarily infected with bacteria. This progression from viral upper respiratory infection to full sinusitis is the most common pathway, occurring in roughly 0.5 to 2 percent of viral colds according to research published in The Lancet.

Viral vs Bacterial vs Fungal: Which Are Contagious?

Viral Sinus Infections (Contagious)

Roughly 90 to 98 percent of acute sinus infections are viral in origin. The causative viruses — rhinovirus, influenza, parainfluenza, adenovirus — spread through respiratory droplets when an infected person coughs, sneezes, or talks. They also survive on surfaces like doorknobs, phones, and countertops for several hours.

When you catch a virus from someone with sinusitis, you may develop a cold, the flu, or your own sinus infection depending on your anatomy, immune response, and nasal health. The virus is contagious, but whether it leads to sinusitis in the next person varies.

Contagious window: Viral sinus infections are most contagious during the first two to three days of symptoms, though the virus can spread for up to two weeks. If your symptoms started as a cold and progressed to sinus pain, you were likely contagious before the sinusitis even developed.

Bacterial Sinus Infections (Not Contagious)

Bacterial sinusitis develops when bacteria like Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis colonize mucus-blocked sinuses. These bacteria are typically already present in your nasal passages in small numbers. The infection arises from your own bacterial flora taking advantage of impaired drainage — not from person-to-person transmission.

Signs that a sinus infection may be bacterial rather than viral include symptoms lasting longer than 10 days without improvement, a high fever above 102 degrees Fahrenheit with facial pain, or a pattern of initial improvement followed by sudden worsening (called “double sickening”).

Fungal Sinus Infections (Not Contagious)

Fungal sinusitis is caused by mold spores like Aspergillus or Mucor that are inhaled from the environment. These infections are not contagious between people. They occur most often in individuals with weakened immune systems, uncontrolled diabetes, or prolonged corticosteroid use. Allergic fungal sinusitis, a milder form, affects people with nasal polyps or a strong allergic response to environmental fungi.

How Long Are You Contagious?

For viral sinus infections, the contagious timeline generally follows this pattern:

• Days 1 to 3: Peak contagiousness. Viral shedding is highest, and symptoms like sneezing and runny nose actively spread droplets.
• Days 4 to 7: Moderate contagiousness. Viral load decreases, but you can still spread the virus through close contact and contaminated surfaces.
• Days 7 to 14: Low contagiousness. Most people are no longer shedding enough virus to infect others, though some viruses (adenovirus, for instance) can persist longer.
• After 14 days: If symptoms continue beyond two weeks, the infection has likely become bacterial, which is not contagious.

A practical rule: you are generally safe to return to work or school once you have been fever-free for 24 hours without fever-reducing medication and your symptoms are clearly improving.

How Sinus Infection Viruses Spread

The viruses behind contagious sinus infections travel through three main routes:

Respiratory Droplets

Coughing, sneezing, and even talking release droplets that can travel up to six feet. These droplets contain viral particles and can be inhaled by people nearby or land on surfaces.

Direct Contact

Shaking hands, sharing utensils, or touching the same objects as an infected person transfers viruses. The virus enters through the eyes, nose, or mouth when you touch your face — which the average person does 16 to 23 times per hour according to a study in the American Journal of Infection Control.

Fomite Transmission

Rhinoviruses can survive on hard surfaces for up to 72 hours. Commonly contaminated objects include phones, light switches, faucet handles, and shared office equipment.

How to Prevent Spreading a Sinus Infection

If you have a viral sinus infection, these measures help protect the people around you:

• Wash hands frequently with soap and water for at least 20 seconds, especially after blowing your nose, coughing, or sneezing.
• Cover coughs and sneezes with a tissue or the inside of your elbow, not your hands.
• Disinfect shared surfaces including phones, keyboards, countertops, and bathroom fixtures daily.
• Avoid close contact with vulnerable individuals including infants, elderly adults, and immunocompromised people during the first three to five days of symptoms.
• Use your own towels, cups, and utensils until symptoms resolve.
• Keep nasal passages clean with saline irrigation using a quality neti pot to reduce viral load in the nasal cavity and minimize sneezing episodes.
• Stay home when symptomatic if possible, particularly during the first 48 to 72 hours when viral shedding peaks.

How to Protect Yourself from Catching a Sinus Infection

You cannot “catch” sinusitis directly, but you can catch the viruses that lead to it. Strengthening your defenses involves:

• Regular handwashing — the single most effective prevention measure according to the CDC.
• Keeping nasal passages moist using saline spray or a humidifier, especially during dry winter months when mucous membranes crack and become more vulnerable to viral entry.
• Managing allergies proactively since chronic nasal inflammation from allergies narrows the sinus drainage pathways and increases infection risk.
• Not smoking — tobacco smoke paralyzes the cilia that sweep mucus and pathogens out of the sinuses.
• Getting annual flu vaccination to reduce your risk of influenza-triggered sinusitis.
• Drinking warm fluids like herbal teas that support respiratory and sinus health to keep mucus thin and flowing.

Sinus Infection Contagiousness: Quick Reference Table

Type	Cause	Contagious?	How It Spreads	Duration of Contagion
Viral sinusitis	Rhinovirus, influenza, etc.	Yes (the virus, not the sinusitis itself)	Droplets, direct contact, surfaces	2 to 14 days
Bacterial sinusitis	S. pneumoniae, H. influenzae, etc.	No	Does not spread person to person	Not applicable
Fungal sinusitis	Aspergillus, Mucor, etc.	No	Environmental exposure only	Not applicable
Allergic sinusitis	Pollen, dust mites, pet dander	No	Triggered by allergens, not pathogens	Not applicable

Frequently Asked Questions

Can I go to work with a sinus infection?

If your sinus infection started as a cold and you are within the first few days, you can still spread the underlying virus. Stay home if possible during peak contagiousness (days one to three). If your doctor has confirmed bacterial sinusitis or your symptoms have lasted more than 10 days, you are not contagious and can return to work when you feel well enough.

Can my child catch my sinus infection?

Your child can catch the virus causing your sinus infection, which may lead to a cold or, in some cases, their own sinus infection. Children are more susceptible because their sinus passages are smaller and their immune systems are still developing. Practice careful hygiene around young children during the contagious window.

Is chronic sinusitis contagious?

No. Chronic sinusitis, defined as sinus inflammation lasting 12 weeks or longer, is not caused by a transmissible pathogen. It results from structural issues (deviated septum, nasal polyps), ongoing allergies, or immune dysfunction.

Should I take antibiotics to stop being contagious?

Antibiotics do not affect contagiousness because they only treat bacterial infections, which are already non-contagious. Most sinus infections are viral and resolve on their own within 7 to 10 days. Antibiotics will not shorten the contagious period of a viral sinus infection.

When to See a Doctor

Seek medical attention if your sinus infection symptoms last longer than 10 days without improvement, you develop a fever above 102 degrees Fahrenheit with severe facial pain, your symptoms improve then suddenly worsen, or you experience vision changes, stiff neck, or confusion — which may indicate the infection is spreading beyond the sinuses. A healthcare provider can determine whether your sinusitis is viral, bacterial, or fungal and recommend the appropriate treatment.

Bottom Line

Most sinus infections stem from contagious viruses, but the sinusitis itself does not jump from person to person. What spreads is the cold or flu virus that triggered it, and that spread primarily occurs during the first few days of illness. Bacterial and fungal sinus infections are not contagious at all. Good hand hygiene, covering coughs, and staying home during peak symptoms are the most effective ways to protect those around you while you recover.