Experts explain why some individuals have close contact with COVID-19 cases multiple times yet still test negative for the virus is not unusual.
Associate Professor Dr. Do Van Dung, Head of the Public Health Department at Ho Chi Minh City University of Medicine and Pharmacy, expressed surprise at the number of people questioning why they themselves did not contract SARS-CoV-2.
“It is normal for individuals who have good immunity and are in close contact with COVID-19 cases not to contract the virus. Additionally, if a person has good immunity and the duration of exposure is short, the risk of transmission is very low“, Dr. Dung stated.
Experts from Ho Chi Minh City University of Medicine and Pharmacy analyzed that for individuals who are fully vaccinated, their bodies have developed immunity against the virus.
He provided an example: if the vaccine’s effectiveness is 90%, it means that out of 100 people exposed, 90 will not get sick, while 10 will. Similarly, if the vaccine’s effectiveness is 60%, then out of 100 people, 40 may become infected.
“Even if vaccinated and possessing antibodies, as long as the COVID-19 pandemic remains a societal issue, we should continue to strictly adhere to the 5K measures to minimize the risk of infection. Even asymptomatic individuals can increase the number of cases, hindering social activities”, Dr. Dung advised.
Light exposure over a long period can also enhance immunity. (Illustrative image).
Additionally, Associate Professor Dr. Do Van Dung discussed exposure scenarios caused by various factors. A specific scenario involves many staff working in quarantine facilities or field hospitals who still do not contract the virus.
The reason is that they practice the 5K measures and maintain good personal protection. Moreover, some individuals may experience mild exposure when in contact with the virus source. Prolonged mild exposure can also lead to increased immunity.
“The 5K measures do not make us completely immune. Suppose someone is infected but with a low viral load; the antibodies can still combat it, thus providing long-term immunity. Without the 5K measures, the viral load increases, raising the risk of severe illness and the likelihood of spreading it to others. Therefore, I do not support the idea of intentionally allowing natural infection”, Dr. Dung remarked.
Associate Professor Dr. Nguyen Viet Hung, Vice President of the Hanoi Infection Control Association, also stated that it is not surprising if one does not contract the virus despite being in a high-risk environment.
According to him, the reasons are the effectiveness of vaccines and strict adherence to the 5K measures. The likelihood of infection depends on factors such as proximity (close or distant), duration, the environment (well-ventilated or enclosed spaces), and whether the individuals are wearing masks.
“Just because you have been in contact with COVID-19 cases does not mean you will be infected. Your own health status is thanks to effective vaccination and adherence to the 5K measures, so it is essential to continue these practices to protect yourself. One should not become disheartened or wait for their turn to get infected”, Dr. Nguyen Viet Hung shared.
