einstein (São Paulo). 31/Oct/2024;22:eAO0495.

Face mask use and viral load in patients with mild symptoms of COVID-19

Murilo Soares

Costa

, Claudia Regina Lindgren

Alves

, Flávio Guimarães da

Fonseca

, Hugo Itaru

Sato

, Raissa Prado

Rocha

, Alex Fiorini de

Carvalho

, Karine Lima

Lourenço

, Nathalia Sernizon

Guimarães

, Elaine Leandro

Machado

, Santuza Maria Ribeiro

Teixeira

, Unaí

Tupinambás

, Ricardo Hiroshi Caldeira

Takahashi

DOI: 10.31744/einstein_journal/2024AO0495

Highlights

■ Probability of infection with a high SARS-CoV-2 viral load depends on mask-wearing habits.
■ The higher probability of infection with high viral load occurs for individuals that don’t use mask regularly [47.3%–79.8%].
■ For individuals who use masks regularly, the probability is 38.6%–52.1%.

ABSTRACT

Objective:

Previous studies indicated that face masks reduce the probability of infection by SARSCoV- 2 but did not examine the relationship between SARS-CoV-2 viral load and mask usage. This study analyzed this relationship.

Methods:

This cross-sectional study evaluated patients admitted to a public Emergency Care Unit in Belo Horizonte, MG, Brazil, between October 2020 and March 2021. Convenience samples were recruited during the study period. Adult patients with COVID-19 symptoms were invited to participate after being examined by a physician according to the Emergency Care Unit routine. This study included 441 adults with mild symptoms diagnosed with COVID-19 via RT-PCR, who were tested until the 14th day after symptom onset. Participants were interviewed about mask usage, oropharyngeal swabs were collected, and the SARS-CoV-2 viral load was measured using RT-PCR. The difference between the SARS-CoV-2 viral load in the groups of individuals who regularly used and did not use masks was subjected to a hypothesis test.

Results:

Of the patients who had swabs collected 1-5 days after symptom onset, 64.9% of those not using masks regularly and 45.5% of those using masks regularly presented a high SARS-CoV-2 viral load. This difference was statistically significant (p=0.0073). Considering only the patients who had swabs collected 4-8 days after symptom onset, 44.1% of those not using masks regularly and 30.8% of those using masks regularly presented a high SARS-CoV-2 viral load; this difference was statistically significant (p=0.0364).

Conclusion:

When people who regularly wear a face mask contract COVID-19, they have a significantly lower probability of having a high viral load of SARS-CoV-2 compared to those who do not regularly wear masks.

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