Outbreak Management and Infection Control

00:01 If we are managing an outbreak, in general there are two approaches that we can consider.

00:07 Early on, an outbreak or an epidemic or pandemic, there is slow transmission and maybe the incidence rate is low In such a time, you can invest in really good case detection.

00:20 Find out who's got it, trace them to figure out who they gave it to and quarantine everybody.

00:28 We call this test, trace and isolate.

00:31 TTI - test, trace and isolate.

00:33 If you do this well, you can prevent the disease from getting out of control.

00:38 Once it starts spreading rapidly though, you need to implement mitigation measures to slow transmission, to flatten the curve, as we now say very commonly.

00:51 And the curve we're talking about is the epidemic curve that we'll talk about later in this course.

00:56 Now many places do both.

00:59 In fact it's advisable to do both, especially once transmission is really quite intense in the community, you don't want to give up your TTI, you want to heighten it.

01:09 So examples of good TTI that have been used to really slow transmission of COVID-19 early on, we see in places like South Korea or Taiwan or Japan, where good investment in case detection and contact tracing has allowed those places to remain mostly open and not be too adversely affected by the disease.

01:39 Those same places still use masks and distancing which are mitigation effects, mitigation techniques.

01:45 So again, nothing prevents you from using both of those things.

01:48 But be aware that when the disease starts to transmit really quite intensely at a high rate, TTI can get overwhelmed and that's when you need some serious mitigation strategies to get the incidence rate down again so that TTI can do its job well.

02:06 Again, TTI is testing, tracing and isolating.

02:10 Many countries now add to this an 'S' for support - test, trace isolate support.

02:15 Support refers to the need to economically support the people who are now being dispossessed by the isolation.

02:24 If you're quarantining for weeks on end, you're not making any money.

02:29 You can't feed your family, you can't pay your rent.

02:31 So public health job maybe to help people that are economically affected by TTI .

02:38 So test, trace, isolate and maybe, support.

02:44 Various infection control strategies we can implement to mitigate transmission once TTI is no longer sufficient to do the job on its own.

02:54 Hand washing Of course.

02:56 Hand washing is one of the most potent methods we have of diminishing transmission of a number of infectious diseases, including the flu and the common cold and possibly COVID-19.

03:08 Hand washing should be high up there in the list of things to advocate for the general public to do.

03:14 It costs nothing and it's easy to do.

03:18 Toilet hygiene is important.

03:20 Flushing the toilet, cleaning regularly, not having crowded toilets.

03:25 This is particularly important for diseases that are spread through the fecal route.

03:31 COVID-19 is thought to potentially be spread fecally, but it's not a major mode of transmission for the disease.

03:42 But toilet hygiene is nonetheless an important thing to consider for a variety of other diseases.

03:48 Masks and gloves, of course.

03:52 When used to protect yourself, we call them PPE, personal protective equipment, but masks at the population level aren't necessarily meant to protect the wearer.

04:04 This is an important consideration and one that's quite confusing for the general public around pandemic time.

04:12 For COVID-19, for example, in nations that have adopted masks have done so to mitigate transmission at the population level.

04:20 So when high-quality medical grade masks like the N95 are worn by hospital staff, they're worn for self protection because those masks are so dense in their fibrous makeup that it's difficult for pathogens to cross them.

04:39 So you are protected.

04:41 For the general public, simple cloth masks are often sufficient because the intent is not to protect the wearer, it's to slow down the breath as it leaves the mouth so that droplets cannot travel more than a few centimeters past the wearer's mouth.

05:01 If you recall, we said that influenza droplets and probably COVID-19 droplets tend to fall within 1 or 2 meters.

05:09 If you wear a mask, that comes down to a few centimeters.

05:13 That means people can walk in front of you and have a lesser likelihood of becoming infected if you are infected.

05:21 When scaled up to the population level, the expectation is that this diminished probability of transmission translates into overall population transmission decrease and it seems to be working in many places around the world.

05:38 Gloves are useful for fomite protection.

05:45 Of course, distancing.

05:47 We talk about droplets again.

05:49 As I mentioned, studies have suggested that most droplets fall to the ground within 1 or 2 meters.

05:56 That distance increases If you're shouting or singing or playing a musical instrument, or a ventilation system is pushing droplets in a certain direction, but on average 1 or 2 meters.

06:09 That's why many countries have those thresholds for keeping people away.

06:15 You must keep within 1 meter, 1.2 meters, 1.5 meters or 2 meters depending upon that nation's standards.

06:22 So if you're far away from somebody who's infected, their droplets will not land on you and you are probably safe.

06:29 Again, none of these mitigation techniques are perfect, but they are good and the expectation is, multiple good mitigation strategies add up to one very good overall public health strategy.

06:45 And last we of course have quarantine.

06:48 So if people are symptomatic, they are asked to isolate at home.

06:53 If we know you are infected, we will compel you to isolate.

06:56 Many nations have quarantine laws that empower the state to legally imprison, for lack of a better word, someone in their home or in a clinic until they recover from the disease or are no longer infectious.

07:10 Thank you very much.