Key facts
- COVID-19 is a disease caused by the SARS-CoV-2 coronavirus. There are a range of signs and symptomsbut hte most common symptoms reported for currently-circulating variants are feverchillsand sore throat.
- Most people make a full recovery without needing treatment. People with severe disease or at risk of developing severe disease should seek medical care as soon as possible.
- Nearly 780 million cases and more than 7.1 million deaths due to COVID-19 have been reported worldwide since December 2019but the actual number is thought to be higher.
- Over 13.64 billion COVID-19 vaccine doses had been administered by the end of 2024. WHO continues to recommend COVID-19 vaccination using a risk-based approach. WHO recommends a single dose for persons who have not yet received a COVID-19 vaccine. For those at high risk of severe COVID-19revaccination may be needed 6-12 months after the most recent dose.
- COVID-19 continues to be a signficant public health concernwith global circulation of the SARS-CoV-2 virus and hospitalizations and deaths continuing to occur.
Overview
COVID-19 is caused by the SARS-CoV-2 viruswhich spreads through the air in infectious respiratory particles from an infected person. Transmission is more likely in close contact or shared indoor spaces. The virus can also spread by touching contaminated surfaces and then the eyesnose or mouth.
Because of increasing immunity from past infections and/or vaccinationmost people recover without treatment. About 6% develop post COVID-19 condition (PCCor long COVID)howeverwhich can cause lasting symptoms such as memory issuesfatigue or breathing difficulties. PCC an affect daily life and requires individualized care.
Older adultspeople with underlying health conditionsand unvaccinated individuals are at higher risk of severe illness. Conditions that increase risk include diabeteshealth or lung diseaseobesity and weakened immune systems.
Health and care workers face higher exposure risk due to their work environment.
Vaccination remains a key preventive measure against severe disease. COVID-19 vaccines continue to provide strong protection against severe illness and death.
Symptoms
People may experience different symptoms with COVID-19.
The most common symptoms are:
- fever
- chills
- sore throat.
Less common symptoms are:
- muscle aches and heavy arms or legs
- severe fatigue or tiredness
- runny or blocked noseor sneezing
- headache
- sore eyes
- dizziness
- new and persistent cough
- tight chest or chest pain
- shortness of breath
- hoarse voice
- numbness or tingling
- appetite lossnauseavomitingabdominal pain or diarrhoea
- loss or change of sense of taste or smell
- difficulty sleeping.
Immediate medical attention should be sought by people at risk of developing severe disease or with the following severe symptoms:
- difficulty breathingespecially at restor unable to speak in sentences
- confusion
- drowsiness or loss of consciousness
- persistent pain or pressure in the chest
- skin being cold or clammyor turning pale or a bluish colour
- loss of speech or movement.
People who have underlying health conditions are at higher risk of developing severe disease when they have COVID-19; they should seek medical help early if worried about their condition. These include:
- people with high blood pressurediabetesobesitychronic lungheartliver and/or kidney disaesescancer or dementia;
- people with rheumatological problems;
- women who are pregnant; and
- people with immunosuppressionsuch as those taking immunosuppressive medication or living with HIV.
The potential consequences of severe COVID-19 include respiratory failuresepsisthromboembolism (blood clots)and multiorgan failureincluding injury of the heartliver or kidneysand death.
In rare situationschildren can develop a severe inflammatory syndrome a few weeks after infection and may require medical attention and hospitalization.
Some people who have had COVID-19whether they needed hospitalization or notcontinue to experience symptoms long after the infectious period has ended. These long-term effects are called post COVID-19 condition (PCCor long COVID). The most common symptoms include fatigueaches and pains in muscles or jointsbreathlessnessheadachesand difficulty in thinking or concentrating. Post COVID-19 condition can affect a person’s ability to perform daily activities such as work or household tasks.
Transmission
SARS-CoV-2the virus causing COVID-19spreads through the air via infectious respiratory particles released when an infected person breathestalkscoughsor sneezes. People are more likely to catch the virus when they are close to the infected personor when they are sharing a closed space with them. The virus can also enter the body when someone touches contaminated surfaces like doorknobs or handles and then touches the eyesnose or mouth.
SARS-CoV-2 circulates throughout the yearcausing outbreaks worldwide without an established seasonal pattern.
Symptoms usually begin 3-6 days* after exposure (1) and last up to10 dayswith some individuals experiencing symptoms for a longer period. Infected people may also spread the virus in the absence of symptoms or in the days prior to developing any symptoms.
Treatment
Medical treatment exists for COVID-19although most people recover from mild illness without needing treatment. For those who need treatmenthealth-care professionals suggest treatments for COVID-19 based on the severity of the disease and the risk of it getting worse. They consider the person’s agesymptomsany coexisting health conditionsand individual factors which might interfere with specific treatments.
Prevention
There are a number of things that people can do to prevent the spread of COVID-19. These are:
- if you are experiencing COVID-like symptoms or have tested positive for COVID-19 stay at home and away from others;
- avoid close contact with individuals who may be at high risk of developing complications if they get sick with COVID-19;
- if you must be around other peoplewear a properly fitted mask if you experience any of the symptoms of COVID-19;
- cover your mouth and nose with a bent elbow or tissue when you cough or sneeze and dispose of used tissues right away and clean your hands;
- clean your hands frequently with soap and water or alcohol-based hand rub; and
- Improve indoor ventilatione.g. by opening windows and doors to increase natural airflow.
Those providing care for high-risk individuals should wear a medical mask and test for COVID-19 if they develop any of the symptoms of COVID-19.
There are a number of things that can be done to avoid becoming sick with COVID-19: These are:
- avoid close contact with people who are experiencing respiratory symptoms;
- avoid entering crowded or poorly ventilated areas if you are at high-risk of developing severe illness should you get sick with COVID-19; if you cannot avoid entering crowded or poorly ventilated areaswear a properly fitted mask; and
- clean your hands frequently with soap and water or alcohol-based hand rub.
To prevent severe illnesshospitalization and death due to COVID-19vaccination should be consideredparticularly if you are at higher risk of serious illnessor if you are a health and care worker caring for those at higher risk.
Additional protective equipment should be considered for health workers taking part in aerosol-generating proceduresin consultation with occupational health and safety advisors.
Vaccines
Since their introductionCOVID-19 vaccines have saved millions of lives around the world by providing protection against severe diseasehospitalizationand death.
In November 2023given that most of the global population had by that time been infected at least onceWHO updated its recommendations stating that a single dose of vaccine can be considered for those who have not yet been vaccinated. Revaccination against COVID-19 may be needed 6-12 months after the most recent dose for high priority groups such as older adults; individuals with severe obesity or multiple significant comorbiditiesincluding diabeteschronic lung diseasesheartliver and kidney diseases; persons with immunocompromising conditions; pregnant women and health and care workers with direct patient contact.
Even though vaccines protect against severe disease and deaththey have limited impact on reducing transmission. It is still possible to spread COVID-19 to others if you are infected after being vaccinated.
WHO advises on COVID-19 vaccination through its Strategic Advisory Group of Experts on Immunization (SAGE). It is important to stay up to date with local recommendations provided by national health authories.
WHO response
During the emergency phase of the COVID-19 pandemicWHO coordinated the global responsesupporting countries with preparednesssurveillancediagnosticsclinical caremedical countermeasuresaccess to oxygencountry readiness and deployment of COVID-19 vaccinesvaccine safety monitoringand evidence-based guidance. WHO recommended 13 vaccines for emergency useguiding countries and UN agencies in their procurementand led global coordination on research and developmentand setting standards for vaccinestestsand treatments. WHO also provided countries with strategic and policy recommendationstechnical guidanceand tools.
The Access to COVID-19 Tools (ACT) Acceleratorlaunched by WHO and partnerswas an unprecedented global effort to rapidly develop and deploy diagnosticstreatmentsand vaccines. COVAXits vaccine pillarproved a ground-breaking global initiative to accelerate vaccine development and productionand ensure equitable global access to COVID-19 vaccines.
Since the Director-General of WHO lifted the Public Health Emergency of International Concern in May 2023 and the emergency phase endedWHO has continued to lead the global COVID-19 responseworking with governments and partners to shift from emergency measures to long-termintegrated management of COVID-19 and other coronavirus threats. Ongoing activities in this respect include regular issuance of Disease Outbreak News postssupporting ongoing researchupdating guidancemonitoring virus trendsand evaluating vaccine composition.
To guide this shiftWHO has developed a strategic and operational plan to help countries manage COVID-19 as part of routine health systems. The plan promotes sustainableevidence-based management of coronavirus threatsaligning COVID-19 responses with broader strategies for respiratory disease control and public health resilience.
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*The Omicron variant virus strainswhich now account for the vast majority of virus strains circulating in humanshave a shorter incubation period than pre-Omicron variant virus strains.---
Reference
1. Assessing changes in incubation periodserial intervaland generation time of SARS-CoV-2 variants of concern: a systematic review and meta-analysis. XuX.WuY.KummerA.G. et al. BMC Med 21374 (2023). https://doi.org/10.1186/s12916-023-03070-8