The message from a potentially viable vaccine COVID-19 is exciting, but even if we start administering an effective sting, it will be a long time before the virus stops spreading. Many countries are still trying to contain dangerous epidemics, and some have had to put in more economically damaging lockdowns. But why is the virus still spreading after months of the basic public health message of hand washing, wearing masks, and social distancing?
It is believed that the virus mainly spreads through Respiratory droplets and formites (contaminated objects or materials such as clothing, furniture and door handles). With this type of spread, most infections occur through close contact, for example between people who are less than 2 meters away from each other.
Because of this, the emphasis has been on face masks, social distancing, and thorough cleansing. Yet it is still very common for people to wear masks improperly (if at all) or to stay 2 meters apart, even after repeatedly disinfecting their hands.
Unsurprisingly, it is prevalent in households, social gatherings, eating together, or when traveling by public transport. In one (n Analysis of 75,465 COVID-19 cases in China78% to 85% of the clusters occurred in households, suggesting that transmission occurs with close and prolonged contact.
in the another study From the United States, infected people passed the virus on to an average of 53% of the people they lived with. This does not explain all disease transmission, however, and other factors are likely responsible for the continued spread as well.
Spread in the air
In the first few months of the pandemic there was considerable debate whether smaller aerosol particles in the air played a significant role in disease transmission. In reality, this debate was artificial, as droplets and aerosolized viruses are on a spectrum of particle size and can be transmitted either way.
While available evidence still points to droplets as the main mode of transmission that exists now better recognition of the role that aerosol spread (in the air) plays. Aerosolized viruses continue to migrate, continue to spread, and can hover in the air for hours, while most of the droplets are likely to land only a few feet from the source.
Think of aerosolized virus particles as cigarette smoke: if you’ve been around a smoker, you’re more likely to inhale a lot of smoke. Some activities like speaking and most of all To sing and scream, increase aerosol and droplet exhalation.
This shows why wearing a mask doesn’t mean you don’t need social distancing too. Barrier methods (such as face masks and visors) can protect against droplets, but they are less effective in protecting against airborne spread, especially with prolonged indoor exposure. The transmission can take place even when people are not facing each other or more than 2 m apart – even if face masks are worn.
Ventilation is important here. In a poorly ventilated room, the concentration of virus particles can likely build up and increase the risk of infection. However, good ventilation will dilute the concentration of virus particles in the air.
It is not yet clear what proportion of the infections are airborne. However, if it turns out to be higher than previously thought, people in high-risk occupations, such as B. Health workers, higher personal protective equipment (PPE).
Likewise, environments in which people are likely to spend long periods of time indoors such as B. Workplaces and classrooms, solutions to improve ventilation or to avoid overcrowding indoors. Public news may also need more emphasis on the importance of indoor ventilation and avoiding overcrowding, in addition to advice on hand washing, face masks, and social distancing.
The other phenomenon is increasingly recognized Driving infections is the role of events that are highly spreading. Super-spreading occurs when a person infects a much higher number of other people than the average. Something Search suggestions Less than 20% of those infected produce over 80% of the infections.
Super common events often occur when People are gathered together in crowded areas and inadequately ventilated indoor spaces. Examples are workplaces such as factories, Bars and night clubs, House parties, gyms, Places of worship and Choirs. Super spreading events can also take place in Hospitals and nursing homes where infection control measures are usually stricter and PPE is used.
Notably, almost all of these events occur indoors. The likelihood of infection is in an enclosed interior 18.7 times higher than outdoors. Unfortunately, people spend more time indoors in winter and this can be increase the risk of transmission, hence the need to minimize household mixing.
Surveys in the UK have shown less than 25% of those infected When prompted, properly isolate yourself and only 12% of your contacts are reported to be fulfilling quarantine requests. This is likely to be a major contributor to the spread of the virus.
But Isolation can be uncomfortable, stressful, and have significant social and economic costs. So more needs to be done to motivate and normalize self-isolation once people experience COVID symptoms or they are quarantined. And more help needs to be given overcome the practical obstacles that prevents people from doing so.
Around It is believed that 20% of people who get COVID will not show any symptomsand many more develop only mild symptoms or show symptoms later in the course of their illness despite being contagious. As a result, these people are unlikely to self-isolate and possibly inadvertently spread infection.
This could be made worse by the fact that mass test programs will inevitably produce a significant number of false negative resultstelling people that because of the limitations of the test, they are not infected when they are actually infected. Asymptomatic people who receive a false negative test may mistakenly believe that they need less protective measures.
In October there was Almost 1 million people infected in the UK. Numbers like these just make it a lot easier for the virus to spread. If we really want to reduce the spread of COVID-19 while waiting for a vaccine without a constant cycle of lockdowns, the best advice for the public remains to act like they may already be infected.