Table 1 Key recommendations and insights of the COVID-19 topics addressed in this review and recommended articles

Science, public health, policy, uncertainty, and communication aspects of COVID-19

Recommended bibliography: [5, 9, 11, 16, 17, 24]

• The COVID-19 pandemic is a stark reminder of ignored yet important gaps, challenges, and opportunities in scientific communication, health education, and policy implementation.

• We need to go beyond “following the science.” The need for and interest in science provides opportunities to create better dialogue between scientists and society.

• Conveying uncertainty does not harm public trust.

• False dichotomies are pervasive and attractive—they offer an escape from the unsettling complexity and enduring uncertainty.

• Debunking misinformation and discouraging black-or-white messaging, all-or-nothing guidance, and one-size-fits-all approaches are valuable endeavors.

• Public health agencies can track COVID-19 misinformation in real time and engage communities and governments to dispel misinformation.

1. Health and lives vs. economy and livelihoods

Recommended bibliography: [8, 23, 25–27]

• Widespread infectious disease transmission negatively impacts both health and the economy.

• Appropriate public health strategies that reduce SARS-CoV-2 transmission safeguard both health and the economy.

• The pandemic response must involve economic, psychological, and sociological views to ensure that lives and livelihoods are protected.

• Public health experts, economists, social scientists, and bioethicists must work jointly to assist governments in shaping the best policies that protect the overall societal well-being.

2. Indefinite lockdown vs. unlimited reopening

Recommended bibliography: [28–40]

• Lockdowns and other stringent public health measures bring social, psychological, and economic harm and competing health risks.

• Regions with widespread transmission should not reopen prematurely in the absence of coordinated and robust countermeasures.

• Multilayered NPIs are needed as part of the road maps for navigating the COVID-19 pandemic.

• Transmission dynamics should inform policy decisions about mitigation strategies and recommendations for reopening.

• Tailored strategies and context-sensitive policymaking fall squarely within the purview of public health and aid in honing our response to COVID-19.

• Harm reduction, continued education, and incentivized messaging work better than shaming and blaming people for violating public health measures.

• Encouraging outdoor activities helps mental and physical welfare, decreases the pandemic and response fatigue, and avoids risk-prone activities from going underground.

• Policies should be constantly reassessed in the name of safety, so that their benefits always outweigh the harms.

• Increasing vaccination rates followed by decreasing numbers of cases may allow gradual relaxation of restrictions.

3. Symptomatic vs. asymptomatic SARS-CoV-2 infection

Recommended bibliography: [41–45]

• SARS-CoV-2 infection ranges from a complete lack of symptoms to critical disease.

• Mild COVID-19 is the most common disease presentation.

• Broadly, there are two types of infected individuals: symptomatic and asymptomatic. The former individuals undergo three distinct stages (usually communicated as if they were different individuals): presymptomatic, symptomatic, and postsymptomatic.

• COVID-19 encompasses a broad clinical spectrum. Fever, cough, fatigue, and anosmia/hyposmia are the most common manifestations.

• Testing (serial if possible), follow-up (ideally 14 days), and a thorough symptom assessment are required to avoid misclassification and truly differentiate asymptomatic individuals from presymptomatic, paucisymptomatic, and postsymptomatic individuals.

• Differential secondary attack rates, viral shedding dynamics, and modeling estimates of contribution to transmission support greater transmission risk from symptomatic and presymptomatic individuals compared with asymptomatic individuals.

4. Droplet vs. aerosol transmission of SARS-CoV-2

Recommended bibliography: [46–53]

• Close-contact transmission, via short-range aerosols and droplets, is the primary transmission mode of SARS-CoV-2.

• Direct (physical) and indirect (via fomites) contact transmission play a minor role in propagating SARS-CoV-2.

• Long-range aerosol transmission occurs under certain conditions: prolonged exposure in enclosed spaces with inadequate ventilation.

• Epidemiological data help determine SARS-CoV-2 transmission mechanisms in real-world conditions.

• Minimum infectious dose, particle size distribution of virus concentrations, and virus viability in particles are unknowns germane to elucidating transmission modes.

• The term “airborne” offers no clear guidance on how to reduce exposure risk and may lead to misunderstandings of transmission or panic.

• Public health messaging on transmission needs nuance and to be accompanied by indications on effective preventive measures.

• Disagreement between different disciplines over SARS-CoV-2 transmission is largely related to semantics.

5. Masks for all vs. no masking

Recommended bibliography: [54–60]

• “Smart masking” is a more accurate term than “universal masking.”

• The case for mask wearing is strongest in high-risk scenarios such as crowded spaces, indoor venues, and unventilated places.

• The case for mask wearing is weakest in marginal-risk scenarios such as outdoor and uncrowded environments where distancing and ventilation are possible.

• In addition to filtration efficiency, fit, and breathability, proper and consistent wearing of masks influences their effectiveness.

• Mask adherence is multifactorial, mediated by sociocultural and psychological factors.

• A social norm of masking is built through well-crafted messaging plus permanent education campaigns on proper mask wearing, the right settings and times to wear a mask, and safe and legitimate exceptions to masking.

• To encourage mask adherence and gain public acceptability, society must be transparently informed about the real-world benefits, potential downsides, and uncertainties.

6. SARS-CoV-2 reinfection vs. no reinfection

Recommended bibliography: [61–65]

• SARS-CoV-2 reinfection remains an overall infrequent event.

• Publication of reinfections is biased toward symptomatic cases. Asymptomatic cases are underreported.

• Existing studies suggest that immune protection following SARS-CoV-2 infection is generally in the range of 5–12 months, though the heterogeneity of induction and durability of immune responses across individuals is acknowledged.

• Epidemiological analyses (including clinical case history assessment) and virological data (nucleic acid amplification testing and comparative genome analysis) are needed to distinguish between reinfection, persistent viral RNA shedding, and recrudescence.

• Additional investigations of SARS-CoV-2 damage to reproductive tissue and potential for persistence need to be determined.