COVID-19 Coronavirus: Symptoms, Treatment & When to Seek Care

What Is COVID-19 and How Does It Spread?

COVID-19 is a respiratory disease caused by the SARS-CoV-2 coronavirus. It spreads primarily through respiratory droplets and aerosols when an infected person coughs, sneezes, talks, or breathes. The virus can also spread by touching contaminated surfaces, though this is less common. COVID-19 is now endemic worldwide with seasonal patterns similar to influenza.

COVID-19 emerged in late 2019 and rapidly became a global pandemic. The disease is caused by a type of coronavirus called SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2). Coronaviruses are a family of viruses that cause respiratory illnesses ranging from the common cold to more severe diseases like MERS and SARS.

The virus has evolved significantly since its emergence, with multiple variants developing over time. Current circulating variants generally cause milder illness than early pandemic strains, partly due to the virus's evolution and partly due to widespread immunity from vaccination and prior infection. However, COVID-19 remains a significant cause of respiratory illness worldwide and continues to cause hospitalizations and deaths, particularly among vulnerable populations.

Understanding how COVID-19 spreads is crucial for prevention. The primary route of transmission is through the air when an infected person releases respiratory particles. These particles can be inhaled by others nearby, especially in indoor settings with poor ventilation. Larger droplets tend to fall quickly, while smaller aerosols can remain suspended in the air for longer periods. Close contact with an infected person, typically defined as being within 2 meters for 15 minutes or more, significantly increases transmission risk.

How the coronavirus affects the body

When SARS-CoV-2 enters the body, it primarily targets cells in the respiratory tract. The virus uses its spike protein to attach to ACE2 receptors found on cells throughout the body, particularly abundant in the airways, lungs, and blood vessels. Once inside a cell, the virus hijacks the cellular machinery to replicate, producing thousands of copies that can infect neighboring cells.

The body's immune response to the infection causes many COVID-19 symptoms. Fever, fatigue, and muscle aches result from inflammatory chemicals released by the immune system. In most people, this immune response successfully controls the infection within 1-2 weeks. However, in some cases, an overactive immune response can cause excessive inflammation, leading to more severe symptoms and complications.

Who is most at risk for severe COVID-19?

While anyone can develop severe COVID-19, certain groups face significantly higher risk. Age is the strongest risk factor, with risk increasing progressively after age 50 and especially after 65. People with weakened immune systems from conditions like cancer, organ transplants, or HIV face elevated risk because their bodies cannot mount an effective defense against the virus.

Chronic medical conditions also increase severity risk. These include diabetes (which impairs immune function and promotes inflammation), heart disease (the cardiovascular stress of infection can trigger complications), chronic lung diseases like COPD or asthma (reduced baseline lung function leaves less reserve), chronic kidney disease (affects immune function and fluid balance), and liver disease. Obesity, particularly severe obesity with BMI over 40, is associated with more severe outcomes due to chronic inflammation and reduced lung capacity.

What Are the Most Common Symptoms of COVID-19?

The most common COVID-19 symptoms include fever, cough, fatigue, sore throat, runny or stuffy nose, headache, and muscle aches. Some people experience loss of taste or smell, though this has become less common with newer variants. Symptoms typically appear 2-14 days after exposure, with most people developing symptoms within 5 days.

COVID-19 symptoms can vary widely from person to person. Some individuals remain completely asymptomatic despite being infected, while others develop severe illness requiring hospitalization. The current predominant variants tend to cause symptoms more similar to a common cold or flu than the original strain did in 2020.

Respiratory symptoms are the hallmark of COVID-19. Cough is one of the most frequent symptoms and may be dry or productive. It often persists longer than other symptoms, sometimes lasting several weeks after the acute infection has resolved. Sore throat and nasal congestion have become increasingly common with recent variants, often appearing early in the illness. Shortness of breath is a more concerning symptom that warrants medical attention, as it may indicate lung involvement.

Systemic symptoms reflect the body's inflammatory response to infection. Fever is common, typically ranging from 38-39°C (100.4-102.2°F), though some people never develop fever. Fatigue can be profound and is often described as unlike normal tiredness - many people feel completely exhausted even with minimal activity. Muscle aches and headaches are frequent complaints that generally improve within the first week.

Loss of taste and smell

Loss of taste (ageusia) and smell (anosmia) were distinctive early symptoms of COVID-19 that helped differentiate it from other respiratory infections. These symptoms occur because the virus can infect the olfactory epithelium - the tissue in the nose responsible for detecting smells. While less common with current variants, when they do occur, these symptoms may persist for weeks or even months after other symptoms have resolved.

Gastrointestinal symptoms

Some people with COVID-19 experience digestive symptoms including nausea, vomiting, diarrhea, and abdominal pain. These symptoms are more common in children but can occur in adults as well. In some cases, gastrointestinal symptoms may appear before respiratory symptoms or may be the only symptoms present. Research suggests the virus can infect cells lining the digestive tract, which may explain these symptoms.

Symptoms in children

Children typically experience milder COVID-19 symptoms than adults. Common symptoms in children include fever, cough, runny nose, sore throat, and fatigue. Some children may develop diarrhea or vomiting. Most children recover quickly without complications. However, a rare condition called Multisystem Inflammatory Syndrome in Children (MIS-C) can occur 2-6 weeks after COVID-19 infection, causing inflammation in multiple organs. Parents should seek immediate medical care if their child develops persistent fever, abdominal pain, rash, bloodshot eyes, or appears very tired after COVID-19.

When Should You Seek Medical Care for COVID-19?

Seek immediate emergency care for difficulty breathing, persistent chest pain or pressure, confusion, inability to stay awake, or bluish lips or face. High-risk individuals (over 65, immunocompromised, chronic diseases) should contact healthcare within 1-2 days of symptom onset to discuss antiviral treatment options. For mild symptoms, most people can safely recover at home.

Knowing when to seek medical care for COVID-19 can be challenging, as symptoms range from trivial to life-threatening. Most people with COVID-19 experience mild illness and can safely manage their symptoms at home. However, certain warning signs indicate the need for immediate medical attention, and high-risk individuals benefit from early healthcare contact even with mild symptoms.

The decision to seek care depends on your symptoms, your risk factors, and how your illness is progressing. While mild symptoms in a healthy young adult rarely require medical intervention, the same symptoms in an elderly person or someone with underlying health conditions may warrant prompt evaluation and potentially antiviral treatment.

When high-risk individuals should seek care

If you are at high risk for severe COVID-19, you should contact your healthcare provider within 1-2 days of symptom onset, even if your symptoms seem mild. Early treatment with antiviral medications like Paxlovid can significantly reduce the risk of hospitalization and death, but these medications work best when started within 5 days of symptom onset - ideally within the first 3 days.

High-risk categories include people aged 65 and older, those with weakened immune systems (cancer treatment, organ transplant recipients, taking immunosuppressive medications), people with chronic conditions (diabetes, heart disease, chronic lung disease, chronic kidney disease, obesity with BMI ≥30), and those who are unvaccinated or incompletely vaccinated.

Symptoms that warrant healthcare contact

Even without emergency warning signs, you should contact healthcare if your symptoms worsen after initially improving (this can indicate secondary bacterial infection), you develop new symptoms after day 5-7 of illness, fever persists beyond 4-5 days, you are having difficulty staying hydrated due to vomiting or diarrhea, or you have concerns about your condition.

How Can You Care for COVID-19 at Home?

Home care for mild COVID-19 includes rest, staying well hydrated, managing fever and pain with acetaminophen or ibuprofen, monitoring symptoms, and isolating from others. Most people recover within 1-2 weeks with supportive care. Use a pulse oximeter if available to monitor oxygen levels - seek care if readings drop below 94%.

The majority of COVID-19 cases can be managed safely at home with supportive care. The goals of home treatment are to relieve symptoms, prevent complications, support the body's natural healing processes, and reduce transmission to others. With proper self-care, most people feel significantly better within a week, though some symptoms like cough and fatigue may linger longer.

Rest is perhaps the most important aspect of recovery. Your body needs energy to fight the infection, and overexertion can prolong illness. Listen to your body - if you feel tired, rest. This is not the time to push through and maintain normal activities. Light movement like walking to the bathroom is fine, but avoid exercise and strenuous activity until you feel fully recovered.

Staying hydrated

Proper hydration is crucial when you're sick. Fever increases fluid loss through sweating, and reduced appetite often means people drink less than usual. Aim to drink fluids regularly throughout the day - water, herbal tea, clear broths, and electrolyte drinks are all good choices. Avoid alcohol and excessive caffeine, which can be dehydrating. Signs of dehydration include dark urine, dizziness, dry mouth, and decreased urination - increase fluid intake if you notice these.

Managing fever and pain

Over-the-counter medications can help relieve COVID-19 symptoms. Acetaminophen (paracetamol) is effective for reducing fever and relieving headache, muscle aches, and sore throat. Follow package directions for dosing and do not exceed maximum daily limits. Ibuprofen and other NSAIDs are also safe to use despite early pandemic concerns - they can help with fever, pain, and inflammation. Some people find alternating between acetaminophen and ibuprofen provides better symptom relief.

For cough, honey (for adults and children over 1 year) can soothe the throat and may help reduce coughing. Over-the-counter cough suppressants may help if cough is interfering with sleep, but productive coughs that bring up mucus generally shouldn't be suppressed. Throat lozenges, warm beverages, and keeping the air moist with a humidifier can also provide relief.

Monitoring your condition

Tracking your symptoms helps you notice if you're improving or worsening. Consider keeping a simple log of your temperature, symptoms, and overall how you feel each day. A pulse oximeter - a small device that clips on your finger to measure blood oxygen levels - can be valuable for monitoring. Normal oxygen saturation is 95-100%; levels consistently below 94% warrant medical attention.

What Treatments Are Available for COVID-19?

COVID-19 treatment depends on severity. Mild cases need only supportive care at home. High-risk patients may benefit from antiviral medications like Paxlovid (nirmatrelvir/ritonavir) if started within 5 days of symptoms. Severe cases may require hospitalization with oxygen therapy, remdesivir, corticosteroids, and other supportive treatments. Early treatment for high-risk individuals significantly reduces hospitalization risk.

COVID-19 treatment has evolved significantly since the pandemic's early days. We now have effective antiviral medications, better understanding of which treatments help (and which don't), and refined protocols for managing severe cases. The appropriate treatment depends on illness severity, individual risk factors, and timing since symptom onset.

For most people with mild COVID-19, no specific antiviral treatment is needed. Supportive care - rest, fluids, fever management - is sufficient, and the body's immune system clears the infection within 1-2 weeks. However, for those at high risk of progressing to severe illness, antiviral treatment can be life-saving.

Antiviral medications for high-risk patients

Paxlovid (nirmatrelvir/ritonavir) is the most widely used antiviral for COVID-19. It works by blocking enzymes the virus needs to replicate. Clinical trials showed it reduces hospitalization and death by about 89% in high-risk unvaccinated adults when started within 5 days of symptom onset. Even with widespread immunity from vaccination and prior infection, Paxlovid provides meaningful benefit for high-risk individuals.

Paxlovid is taken as three pills twice daily for 5 days. The ritonavir component helps maintain effective drug levels but can interact with many other medications. Your healthcare provider will review your medications for potential interactions. Common side effects include altered taste (often described as metallic) and diarrhea.

Remdesivir is an intravenous antiviral approved for COVID-19 treatment. It's used primarily for hospitalized patients or high-risk outpatients who cannot take Paxlovid. Given as infusions over 3 consecutive days for outpatients, it reduces hospitalization risk when started early. For hospitalized patients, treatment duration is typically 5 days.

Hospital treatment for severe COVID-19

Patients with severe COVID-19 requiring hospitalization receive a combination of treatments tailored to their condition. Supplemental oxygen is often needed, ranging from low-flow nasal cannula to high-flow oxygen or mechanical ventilation in critical cases. The goal is maintaining adequate oxygen delivery to vital organs.

Corticosteroids like dexamethasone reduce inflammation and have been shown to reduce mortality in patients requiring oxygen. They're a cornerstone of treatment for moderate to severe COVID-19. Additional immunomodulatory treatments may be used for specific situations, such as tocilizumab or baricitinib for patients with rapidly worsening inflammation.

Anticoagulation (blood thinners) is typically given to hospitalized COVID-19 patients because the infection increases blood clot risk. Patients may also receive treatment for bacterial infections if they develop secondary pneumonia, nutritional support, physical therapy to prevent deconditioning, and close monitoring in intensive care settings when needed.

How Can You Prevent COVID-19 Infection?

COVID-19 prevention centers on vaccination, which significantly reduces severe illness risk. Additional measures include staying home when sick, improving indoor ventilation, hand hygiene, and wearing masks in high-risk situations. High-quality masks (N95/KN95) provide better protection than cloth masks. Vaccination remains the single most effective prevention strategy.

While achieving complete protection from COVID-19 is impossible given its widespread circulation, multiple strategies can significantly reduce your risk of infection and, importantly, your risk of severe illness. The combination of vaccination, behavioral measures, and environmental modifications provides layered protection.

Vaccination has fundamentally changed the COVID-19 landscape. While vaccines don't completely prevent infection, they dramatically reduce the risk of severe illness, hospitalization, and death. Updated vaccines targeting current circulating variants provide the best protection. The immune response from vaccination, even if it doesn't prevent infection, helps the body control the virus more effectively, leading to milder and shorter illness.

Vaccination recommendations

Current guidelines recommend COVID-19 vaccination for everyone aged 6 months and older. For most adults, an updated vaccine annually is recommended, similar to influenza vaccination. Certain groups benefit from more frequent boosting, including adults 65 and older (higher risk of severe disease and waning immunity), people who are immunocompromised (may have weaker vaccine response and higher risk of complications), and those with certain chronic medical conditions.

Both mRNA vaccines (Pfizer-BioNTech, Moderna) and protein-based vaccines (Novavax) are available. All approved vaccines provide good protection against severe disease. Choose whichever vaccine is available and acceptable to you - the most important thing is getting vaccinated, not which specific vaccine you receive.

Behavioral prevention measures

Staying home when sick is one of the most effective ways to prevent transmission. If you have COVID-19 symptoms or test positive, avoid contact with others until you've recovered. This simple measure prevents many infections. Good hand hygiene - washing hands frequently with soap and water or using hand sanitizer - helps prevent both direct transmission and transmission from contaminated surfaces.

Masks provide a physical barrier that reduces respiratory particle transmission. Higher quality masks (N95, KN95, KF94) filter more particles than surgical or cloth masks and are recommended for high-risk settings like healthcare facilities or when around vulnerable individuals. Masks work best when worn consistently and fitted properly over both nose and mouth.

Environmental measures

Improving indoor ventilation reduces COVID-19 transmission by diluting viral particles in the air. Strategies include opening windows when possible, using fans to improve air circulation, upgrading HVAC filters to higher efficiency ratings (MERV-13 or higher), and using portable HEPA air purifiers in rooms without good ventilation. Outdoor gatherings are inherently lower risk than indoor ones because of natural ventilation.

What Is Long COVID and How Long Does It Last?

Long COVID refers to symptoms persisting or developing more than 4 weeks after initial COVID-19 infection. Common symptoms include fatigue, brain fog, shortness of breath, and exercise intolerance. Studies suggest 10-30% of people experience some long COVID symptoms. Risk factors include severe initial illness, female sex, older age, and pre-existing conditions. Most improve over time, though some symptoms may persist for months or years.

Long COVID, also known as post-COVID condition or post-acute sequelae of SARS-CoV-2 infection (PASC), has emerged as a significant challenge following the acute pandemic phase. While most people recover completely from COVID-19 within a few weeks, a substantial minority experience persistent symptoms that can significantly impact quality of life and ability to function.

The condition is frustratingly variable - symptoms differ from person to person, can fluctuate over time, and may affect multiple organ systems simultaneously. This variability has made long COVID challenging to study and treat, though research is advancing our understanding of its mechanisms and potential treatments.

Common long COVID symptoms

Fatigue is the most commonly reported long COVID symptom, affecting about half of those with persistent symptoms. This isn't ordinary tiredness but often profound exhaustion that doesn't improve with rest. Many describe post-exertional malaise - worsening symptoms after physical or mental exertion - similar to what's seen in chronic fatigue syndrome.

Cognitive difficulties, commonly called "brain fog," affect many long COVID patients. Symptoms include difficulty concentrating, problems with memory (especially short-term), word-finding difficulties, and slowed thinking. For some, these symptoms significantly interfere with work and daily life. Research suggests inflammation, blood vessel damage, or direct effects on brain cells may contribute.

Respiratory symptoms including shortness of breath, cough, and chest tightness can persist long after the acute infection. Some patients have measurable lung damage on imaging or pulmonary function tests, while others have normal tests despite significant symptoms. Exercise intolerance - becoming unusually short of breath or fatigued with exertion - is common even without other respiratory symptoms.

Other frequently reported symptoms include heart palpitations and racing heart (sometimes related to dysautonomia/POTS), sleep disturbances, headaches, persistent changes in taste or smell, joint and muscle pain, depression and anxiety, and gastrointestinal problems.

Who develops long COVID?

While anyone can develop long COVID, certain factors increase risk. Severe initial COVID-19 illness requiring hospitalization significantly increases long COVID risk, though long COVID can follow even mild infections. Women appear more susceptible than men, possibly related to autoimmune mechanisms. Older age and pre-existing conditions (especially obesity, asthma, and diabetes) increase risk. Some studies suggest that vaccination reduces long COVID risk, even when infection occurs.

Managing long COVID

There is currently no specific cure for long COVID, and treatment focuses on managing individual symptoms. This may include physical rehabilitation and graded exercise programs (carefully designed to avoid triggering post-exertional malaise), cognitive rehabilitation for brain fog, medications for specific symptoms like pain or sleep problems, mental health support for anxiety and depression, and pacing strategies to manage energy levels.

Many long COVID clinics have been established to provide coordinated, multidisciplinary care. If you're experiencing persistent symptoms after COVID-19, discuss with your healthcare provider about referral to specialized care. Most people with long COVID do improve over time, though recovery may be slow and incomplete in some cases.

How Is COVID-19 Diagnosed and When Should You Test?

COVID-19 is diagnosed primarily through rapid antigen tests (available for home use) or PCR tests (more sensitive, performed at healthcare facilities). Test when you have symptoms, after exposure to someone with COVID-19, or before visiting high-risk individuals. Rapid tests are most accurate when done 2-3 days after symptom onset. A negative rapid test with ongoing symptoms should be repeated.

Accurate testing remains important for COVID-19 management, helping individuals know when to isolate, when to seek treatment, and when it's safe to resume normal activities. Understanding the different test types, their strengths and limitations, and when to use them helps ensure appropriate testing decisions.

Two main types of tests detect active COVID-19 infection: molecular tests (PCR) and antigen tests. Both detect the virus itself, though through different mechanisms, and can identify people who are currently infected. A third type, antibody tests, detects past infection or vaccination response but isn't useful for diagnosing current illness.

Rapid antigen tests

Rapid antigen tests are widely available for home use and provide results within 15-30 minutes. They work by detecting proteins on the surface of the SARS-CoV-2 virus. These tests are most accurate when viral levels are high, typically around days 2-5 of symptoms. A positive rapid test is highly reliable and generally doesn't need confirmation. However, false negatives can occur, especially very early or late in infection. If you test negative but have symptoms, repeat the test 24-48 hours later.

PCR tests

PCR (polymerase chain reaction) tests are the most sensitive COVID-19 tests, capable of detecting very low levels of viral genetic material. They're performed at healthcare facilities, laboratories, or some pharmacies, with results typically available within hours to a few days. PCR tests are recommended when a highly accurate result is needed, when rapid tests are negative but COVID-19 is strongly suspected, or for certain medical or travel requirements. Note that PCR tests can remain positive for weeks after infection due to detecting residual viral fragments, even after you're no longer contagious.

When to test

Testing is recommended when you develop COVID-19 symptoms (even mild ones); after known exposure to someone with COVID-19 (test 3-5 days after exposure); before visiting high-risk individuals to reduce their exposure risk; and as required for certain activities, travel, or healthcare settings. If you're high-risk and test positive, contact healthcare promptly to discuss antiviral treatment options.