One day, Kevin got an annoucement that student will attend to school. But, the student must wear a mask and maintain a distance with other poeple in the school. Other than that, student must be vaccinated and take care each others health.
A few days later, Kevin went to the hospital and got vaccinated.
Yeay !! I got vaccinated. Now I won't get  infected by corona virus.
After that, Kevin went hangout with his friends. But Kevin doesn't wear a mask and doesn't keep his distance from his friends. Because he thinks that after got vaccinated, he won't get infected by corona virus.
A few days later, Kevin attend to school. In the school, Kevin feeling not well and start coughing and sneezing.
U hughhh.....Haa ciwwwww !!! 
Oh My God Kevin, what have you done....
After been checked, the doctor said that Kevin have been infected by corona virus.  Not only that, his other friends also been infected because they doesn't wear a mask.
It seems that Kevin and the other student got infected by corona virus....
Okay doctor, I'm so sorry...
Kevin feels bad about the accident that he made and spreading the virus to his friends.
Next time, wear a mask and maintain a distance with other people wherever you go. Okay ?