Primary prevention
Vaccines
The World Health Organization (WHO) currently recommends vaccination based on priority groups that reflect the risk of severe disease and death.[371]
Numerous COVID-19 vaccines are available globally.
mRNA vaccines: Comirnaty® (Pfizer/BioNTech); Spikevax® (Moderna).
Protein subunit vaccines: Nuvaxoid® (Novavax); Corbevax® (Biological E limited).
Inactivated virus vaccines: Covilo® (Sinopharm); CoronaVac® (Sinovac); VLA2001 (Valneva); BBV152 Covaxin® (Bharat Biotech).
Adenovirus vector vaccines: Convidecia® (Cansino).
Vaccine availability differs between geographic locations and you should consult your local public health authority for more information on which vaccines are available in your area.
Monovalent or bivalent vaccines may be available. Vaccines are being adapted to better match the currently circulating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants and are being updated annually, similar to the influenza vaccine.
Consult your local guidelines for information on who to vaccinate, choice of vaccine, dose schedule, and contraindications/cautions.
Administer the vaccination series according to local public health authority recommendations.
The schedule generally consists of a primary vaccination series (additional doses may be recommended for immunocompromised people), and booster doses in certain populations. Vaccines are included in routine immunization schedules in some countries.
Vaccines are effective at reducing the risk of symptomatic, severe, and critical disease.
A Cochrane review found that most vaccines reduce (or likely reduce) the proportion of people with symptomatic disease. There is high-certainty evidence that some vaccines may reduce severe or critical disease. There is insufficient evidence to determine whether there was a reduction in mortality compared with placebo. Most studies assessed the vaccine for a short period after injection (2 months); therefore, it is unclear whether protection wanes over time. Most studies were conducted before the emergence of variants of concern.[372]
Evidence in special patient populations is limited.
Pregnancy: systematic reviews and meta-analyses have found no evidence of a higher risk of adverse outcomes in pregnant women with mRNA vaccines. However, the evidence is of low certainty, the data have limitations, and continued monitoring is needed to further assess the risk.[373][374][375][376][377] Vaccination during pregnancy may protect the infant against infection and reduce the risk of hospitalization; however, further research is required.[378][379][380]
Breastfeeding: vaccine-derived mRNA has been detected in the breast milk of women who received vaccination within 6 months of delivery. The implications of this are unknown, and further research is required.[381][382]
Children and adolescents: available evidence suggests safety and efficacy are acceptable in children and adolescents. Older children and adolescents were at significantly increased risk of adverse reactions after vaccination compared with younger children. There is a need for additional multicenter, large-sample studies and long-term follow-up data.[383]
Adverse events vary and may depend on the specific vaccine. Consult the relevant prescribing information for more information.
Rare adverse events include: myocarditis/pericarditis; transverse myelitis; Guillain-Barre syndrome; acute peripheral facial paralysis; vaccine-induced immune thrombocytopenia and thrombosis and other thromboembolic events; and immune thrombocytopenia. See Complications.
Other serious adverse events have also been reported in clinical trials, case reports, case studies, and observational studies.[384][385][386][387][388][389][390][391]
A secondary analysis of phase 3 randomized clinical trials of mRNA vaccines in adults found an excess risk of serious adverse events of special interest of 12.5 per 10,000 vaccinated, which suggests a higher risk than initially estimated at the time of emergency authorization.[392]
One self-controlled case series analysis found minimal evidence of an increased incidence of cardiac or all-cause mortality overall in the 12 weeks following vaccination (for all vaccines). However, there is evidence of a smaller increased incidence of cardiac or all-cause mortality after a second dose of an mRNA vaccine in males, and after a first dose of a non-mRNA-based vaccine among females.[393] Another self-controlled case series analysis found that vaccination was associated with an increased risk of cardiac-related mortality, especially among males.[394]
Vaccine adverse effects have similarities and differences to long COVID, and these syndromes should be differentiated from each other. Further research is required.[395]
Report all suspected adverse events via your local reporting system (this is mandatory in some countries).
mRNA vaccines have not been authorized for use in humans previously, so there is no long-term safety data available.
Pre-exposure prophylaxis
Tixagevimab/cilgavimab, a long-acting neutralizing monoclonal antibody combination with activity against SARS-CoV-2, may be authorized in some countries for pre-exposure prophylaxis.
However, guidelines do not currently recommend tixagevimab/cilgavimab for pre-exposure prophylaxis, as currently circulating SARS-CoV-2 subvariants are unlikely to be susceptible.[396][397][398][399]
Evidence for the use of tixagevimab/cilgavimab is limited. A systematic review and meta-analysis found that tixagevimab/cilgavimab was associated with a reduction in RT-PCR positivity, symptomatic disease, severe disease, hospitalization, intensive care unit admission, need for oxygen, and mortality compared with no treatment or another alternative treatment. Its activity may be reduced for the Omicron BA.1 and BA.2 subvariants, but it likely maintains most of its activity against the BA.4 and BA.5 subvariants.[400]
No drugs used for prophylaxis (e.g., ivermectin, hydroxychloroquine, lopinavir/ritonavir) have provided convincing evidence for a reduction in the risk of infection. However, much of the evidence remains very low-certainty.[401][402]
The WHO strongly recommends against administering hydroxychloroquine prophylaxis to people who do not have COVID-19, based on high-certainty evidence.[396]
Infection prevention and control for healthcare professionals
Consult local infection prevention and control protocols; only basic principles from the World Health Organization (WHO) guidelines are detailed here.[403]
Screen all people, including patients, visitors, and others entering the facility, for COVID-19 at the first point of contact with the health facility to allow for early recognition.
Immediately isolate all suspected or confirmed cases in a well-ventilated area that is separate from other patients, preferably in an isolation room, area, or single-patient room, if available. Maintain a physical distance of at least 3 feet (1 meter) between patients (increase distance where feasible).
Implement standard precautions at all times, which include, but are not limited to:
Risk assessment
Hand hygiene
Respiratory hygiene and cough etiquette
Patient placement
Personal protective equipment
Aseptic technique
Environmental cleaning
Waste management.
Implement additional transmission-based precautions (contact, droplet, and airborne) when providing direct care for suspected or confirmed cases.
A respirator or medical mask should be worn along with other personal protective equipment (i.e., gown, gloves, eye protection) when providing care to a suspected or confirmed case.
A respirator should be worn in the following situations: in care settings where ventilation is known to be poor or cannot be assessed, or the ventilation system is not properly maintained; based on the worker’s values and preferences.
Appropriate mask fitting for respirators and medical masks should always be ensured, as should compliance with appropriate use of personal protective equipment and other standard or transmission-based precautions.
Universal masking is strongly recommended in health facilities when there is a significant impact of COVID-19 on the health system.
Implement airborne precautions when performing aerosol-generating procedures, including placing patients in an airborne infection isolation room and wearing a respirator.
A respirator should always be worn along with other personal protective equipment while performing aerosol-generating procedures, and in settings where these procedures are regularly performed on patients with suspected or confirmed disease (e.g., intensive care units, emergency departments).
Some countries and organizations recommend airborne precautions for any situation involving the care of a COVID-19 patient.
All specimens collected for laboratory investigations should be regarded as potentially infectious.
Appropriate personal protective equipment gives healthcare workers a high level of protection.
A rapid review and meta-analysis found that wearing personal protective equipment conferred significant protection against infection compared with not wearing it. High-certainty evidence indicates that using N95 masks significantly reduces the risk of infection. No effect was found for wearing gloves and gowns. There is a lack of evidence for different combinations of personal protective equipment.[404]
An expert panel statement informed by review-level evidence (as of May 2022) concluded that N95 respirators (or their equivalent) may be more effective than surgical masks in reducing the risk of infection in the mask wearer (low confidence) based on epidemiologic evidence (usually of low or very low certainty) from SARS-CoV-2 and other coronaviruses.[405]
One systematic review and meta-analysis found a protective effect for N95 respirators (particularly for medical staff), but surgical masks were not associated with a lower risk of infection.[406]
Healthcare workers who have signs or symptoms of infection should be excluded from their activities at work that require providing in-person care to patients or other activities in the healthcare facility where they are in contact with other health and care personnel.
Consultation with the occupational health and safety department is recommended, and local policies should be followed regarding isolation (e.g., 5 days if asymptomatic, 10 days if symptomatic) and testing (e.g., rapid antigen testing may be used to reduce the period of isolation).
Patients can be managed remotely by telephone or video consultations depending on local protocols.[407]
Detailed infection prevention and control guidance is available:
Infection prevention and control for the general public
Public health recommendations vary between countries and you should consult your local guidance.
It is generally recommended that people stay at least 3 feet (1 meter) away from others (recommendations on distance vary between countries), wash their hands often with soap and water (or hand sanitizer that contains at least 60% alcohol), cover coughs and sneezes, avoid crowds and poorly ventilated spaces, clean and disinfect high touch surfaces, monitor their health and self-isolate or seek medical attention if necessary, and get vaccinated.[408]
WHO: advice for the public – coronavirus disease (COVID-19) Opens in new window
The WHO strongly recommends mask use in community settings in higher-risk situations regardless of the local epidemiologic situation (e.g., poorly ventilated spaces, following recent exposure to COVID-19 when sharing spaces with others, people at high risk of severe complications), and conditionally recommends a risk-based approach for mask use in community settings in other situations.[403] Public health recommendations vary between countries and you should consult your local guidance.
There is no high-quality or direct scientific evidence to support the widespread use of masks by healthy people in the community setting.
A Cochrane review, which included results of studies from during the COVID-19 pandemic, found that the pooled results of randomized controlled trials did not show a clear reduction in respiratory viral infection with the use of surgical masks. Mask use in the community setting probably makes little or no difference to the outcome of laboratory-confirmed influenza or COVID‐19 compared with not wearing masks (moderate-certainty evidence). There were no clear differences between the use of N95/P2 respirators and surgical masks in healthcare workers when used in routine care to reduce the risk of respiratory viral infection, and the evidence was very uncertain.[409]
A living rapid review found that masks may be associated with a small reduction in risk for infection in community settings (low- to moderate-strength evidence), and surgical masks and N95 respirators may be associated with a similar infection risk in routine patient care settings.[410][411]
The only randomized controlled trial to investigate the efficacy of masks in the community during the pandemic found that the recommendation to wear surgical masks when outside the home did not reduce infection compared with a no mask recommendation. However, the study did not assess whether masks could decrease disease transmission from mask wearers to others (source control).[412]
A systematic review in children found no effect of mask wearing on infection or transmission across the majority of observational studies. There were no randomized controlled trials in children.[413]
Cloth masks have limited efficacy in preventing viral transmission compared with medical-grade masks and the efficacy is dependent on numerous factors (e.g., material type, number of layers, fitting, moisture level), and may result in increased risk of infection.[414][415]
Harms and disadvantages of wearing masks include headache, breathing difficulties, cognitive fatigue, facial skin lesions, irritant dermatitis, worsening acne, difficulty wearing masks by certain members of the population (e.g., children, people with learning disabilities, mental illness or cognitive impairment, asthma, chronic respiratory or breathing problems, facial trauma or recent oral maxillofacial surgery, living in hot and humid environments), psychological issues, difficulty communicating, poor compliance, waste disposal issues, and increased viral load. There are insufficient data to quantify all of the adverse effects that might reduce the acceptability, adherence, and effectiveness of face masks.[403][416][417][418]
Many countries implemented nonpharmaceutical interventions during the pandemic in order to reduce and delay viral transmission (e.g., social distancing, city lockdowns, stay-at-home orders, curfews, nonessential business closures, bans on gatherings, school and university closures, remote working, quarantine of exposed people). However, there was no clear, significant beneficial effect of more restrictive nonpharmaceutical interventions compared with less restrictive nonpharmaceutical interventions in any of the countries studied.[419]
Many countries implemented travel-control measures during the pandemic including complete or partial closure of borders, entry or exit screening, and/or quarantine of travelers. However, evidence to support the use of these measures was of low to very low certainty.[420][421][422] [
]
[ ]
Lifestyle modifications
There are a lack of data on the use of lifestyle modifications and their impact on COVID-19. Further research is required.
Lifestyle modifications (e.g., smoking cessation, weight loss, nutritious diet) may help to reduce the risk of infection, and may be a useful adjunct to other interventions.[423][424]
The WHO recommends that tobacco users stop using tobacco given the well-established harms associated with tobacco use and second-hand smoke exposure.[228]
Use of this content is subject to our disclaimer