How would you explain COVID-19 lockdown to a 4 year old given that the lockdown might be in place for months in London?
First of all, recognize that your concerns may not be the same as your four year old's concerns. This has two implications:
Your child may be worried about things you couldn't have thought of. Your child is likely shielded from or doesn't understand a lot of what's going on, and that can also mean that they don't have access to bits of information that would actually be reassuring. Encourage your child to ask questions about corona, so that they're not left to ponder on their own things that may seem frightening.
You are likely worrying about outcomes your child has no thought of. Try not to pass on your own fears to your child. If pre-school is closed and one parent has to stay home from work to care for the child, recognize that this may be viewed as a mainly positive outcome to the child.
With my three year old, I emphasize that all closures and restrictions (writing from Sweden, we're not currently in full lockdown) are not - ultimately - to protect us from disease, but to protect our elderly from catching it from us. I find that framing to be appealing because it's both true, and I imagine it's less scary to a young child to hear how we all have to chip in and make sacrifices to protect another group, than to convey an image that it's actually unsafe for them to step outside.
Why we should wash our hands and what's so good about vaccines are some things we talk about normally, and the current situation is a good opportunity to put that into context. You can say that it is to avoid this that we vaccinate against a lot of other things, and that scientists are working on a vaccine against this too. That perhaps once your kid will have children of their own, and they will receive a corona vaccine as well in the routine program, and your child will be able to tell their children how they remember what it was like before the vaccine. Washing hands has been a constant battle. Now we've introduced a longer routine, which involves singing a 20-second-long song, and compliance has (temporarily, I assume) increased.
Consider whether you are changing your own behavior in a manner which may require explanation. For instance, if you are suddenly buying groceries in conspicuously larger quantities than normal, or even if they may have seen the images of empty shelves, you may want to point out that you and others are trying to reduce your number of trips to the grocery store, and hence the number of chances you may infect some at-risk person, lest they think that you're actually going to run out of food.
As an adult, it's easy to become consumed by this. We like to stay updated about what's going on in the world, and this is certainly a main event, and a rapidly evolving one. For my own sake, I could easily bingewatch news for the greater part of the day, and spend the remainder hypothesizing over different future scenarios. Recognize that a young child's world is smaller than yours. Talk about it as a thing that's happening right now, but make sure most of your interactions revolve around normal day to day activities. The above is addressing your question, how to talk about corona, but also make sure you don't talk exclusively about corona.
Some great resources exist already for this. Here are a few my child's school has suggested, which I also think are fantastic.
The CDC site on talking to children about Coronavirus focuses both on parents ("remain calm and reassuring," "provide information that is honest and accurate," etc.) and on facts that are presented in a way children can understand - what is COVID-19, what can I do to avoid getting COVID-19, etc.
The National Association of School Psychologists resource page includes much of the same information as well. In particular I like the age appropriate suggestions:
Early elementary school children need brief, simple information that should balance COVID-19 facts with appropriate reassurances that their schools and homes are safe and that adults are there to help keep them healthy and to take care of them if they do get sick.
This is also appropriate to four year olds. The worst thing for them is fear, because they don't have anything to gauge this by - for that matter, most of us don't either; but we have more context than they do. Give them that context when you can, but when you can't, reassure them that this will get better, and while there will be some bad things that happen because of it, a lot of people are working hard on this to make it better for everyone, and that you will take care of them if they do get sick.
To you and me, this lockdown is unprecedented. To a four year old child, everything is unprecedented. They are used to new things happening because new things happen all the time to them.
“There are lots of dangerous germs around at the moment that can stick to your hands and make you sick if they get into your mouth, that’s why we don’t meet other people unless we have to, and that’s why we have to wash our hands for a long time with hot water and soap, especially after we touched things and before we eat”.
Kids don’t have to understand it completely, just enough to make them act in a safe way.
I did this as a pen-and-paper game with my small child. It was dotted paper, I said "each of these dots is a person, now look I'm going to make this one sick." I coloured in one dot with a pen. "This is day one."
"The next day this one makes two more people sick." I took a different coloured pen and coloured two adjacent dots, and crossed off the first. "Now three people are sick."
You can see where this is going. A four-year old can follow a "circle two dots and cross out one of yesterday's" procedure, and changing colours each "day" makes it easy to keep track.
When the sheet of paper is full, say "this is a whole town of people, they're all sick now, what will happen tomorrow? There will be three pages full of dots."
This one is explicitly aimed at kids: Coronavirus Explained! (For kids)
This one is a round table with the New Zealand Prime Minister: Coronavirus COVID-19 update with PM Jacinda Ardern, Dr Michelle Dickinson and Dr Juliet Gerrard
Thank you, Mr. President. It's not easy for me either. I also stay at home all the time. I don't shake hands with anyone, not in a long time. I wash my hands thoroughly, every day, as it should be, over and over again. We just have to fight this virus. It is more important than ever that we all help each other. Especially the older generation. The have the greatest risk. And those who are sick. By giving them space and not shaking hands. We have to see that we take it incredibly seriously. Otherwise we all have to stay in quarantine at home. Then we all can’t go out anymore. I really hope everyone takes it seriously. Roger Federer
I’m sure a 5 years old child will understand it.
Most answers focus on explaining why it is important that the virus is super infectious and what we can do to decrease the spread. These are incredibly valuable. For me, it helps if you understand what a virus is. I think the basic concept isn't that difficult.
I use lego as a simplified analogy. I generally dislike simplified analogies in arguments because by definition they leave out details but they can have a function to make complex concepts easier to understand.
Lego has these blue instruction manuals. They tell you how to make all different sort of things. It can be cars, helicopters, houses, whole fire stations. Now, let's imagine there would be such a blue book which would instruct you to build a robot. And not just any kind of robot, this would be like a super lego mindstorm robot which can actually read these blue books himself and build lego cars, helicopters, etc. That would be quite the awesome robot. And think of it, anybody with the right amount of lego could be told how to build the robot if you would just send them the blue instruction book! Wouldn't that be fun if someone send us the book? In reality, there is no such book for lego of course, but in a way there are such books for all plants and animals. They are really tiny and you only see them if you have a really really good magnifying glass. You can actually look up pictures on the internet. They look nothing like lego books but they work just the same. They can be read by tiny tiny machine like parts, which are a bit like factory robots. They read the books to build all living things. They build leaves, trunks, bones, skins, eyes, legs, hands, everything! These books is what people mean when they talk about DNA. That is an abbreviation for what it is made of. We can look it up what it stands for but it is not really important now.
What is important is how viruses work. What is really special about viruses is that unlike all other living things, they don't have the robot like machines to read the blue instruction manuals. What they do, is they try to get inside and, while no one is looking, put a few extra pages in the blue book of others. If they succeed, the reading robots never noticed and just follow the build. You know how sometimes lego instructions contain extra mini cars in a set. You build them in just a few pages. And sometimes with a lego instruction it says "2x". The pages of viruses are like that but they just say: "go back and build another one".
This way millions of virusses get build and they leave your body if you sneeze or go to the toilet. You cannot see them and some can stick to your fingers and then get on anything you touch. Then they might stick to someone elses finger and if they touch their mouth the virus could get in and if they manage to stick their few pages in the other persons books they have successfully repeated the cycle.
Depending on the child I would add extra details, like explaining the concept of cells and that each cell has their own copy of DNA, the concept of an immune system to protect against invaders, mutation and repair systems by having a double copy of each. Procreation where copies are passed on, explaining why donkeys make small donkeys and fish make small fish. They pass on their own DNA which is a combination of the 'books' of two parents, mixing up pages (combining the color scheme of the lego bricks) and random mutations. And from there it is only a small step to explaining that if living things produce more offspring than two while the population stays more or less the same than the mutations/combinations that help you find food and find a partner will accumulate, conversely, lets say a mutation makes you blind, then that mutation dies of. If a mutation improves something, it will remain.
To my 3 years old niece we have told that we have to stay inside because there are invisible "little monsters" which can make people badly sick, and we don't want to come in touch with them.
The "little monsters" were more easy for her to understand than the concept of virus/bacteria, and she has been happy with that explanation.
I am a psychotherapy student. :)
CAMH (Centre for Addiction and Mental Health) is a leading institute that offers mental health research and advice. See their resource centre for mental health and COVID-19. They also have a section about how to talk to children. http://www.camh.ca/en/health-info/mental-health-and-covid-19
I strongly advise looking for institutes that are already active in mental health for direction about this (some links have been posted here already). Children usually understand things very well. They may not understand the logic but they definitely feel the emotions that parents may think they can hide them from. Children are some of the first people in a family to notice things that go wrong (the coldness between parents for example, etc), so it is very important to acknowledge the fear or emotion or any emotions that you or they are feeling. It is not so much about explaining what is going on in a logical way. More so, it is about seeing how they feel about this. Stay with each other and try to be honest and real. :)