Mark a period of time in a time-series-plot

First, let's create some fake data:

d <- c("2019-01-01", "2019-01-02", "2019-01-03", "2019-01-04", "2019-01-03", "2019-04-06", "2019-04-03", "2019-05-07", "2019-05-03", "2019-05-03", "2019-05-03", "2019-05-03", "2019-06-03", "2019-06-03", "2019-06-03", "2019-06-03", "2019-06-03", "2019-06-03", "2019-06-03", "2019-07-03", "2019-07-03", "2019-07-04", "2019-08-03", "2019-09-05", "2019-09-03", "2019-09-03", "2019-09-06", "2019-09-08", "2019-10-03", "2019-11-03", "2019-11-03", "2019-11-03", "2019-11-03", "2019-11-03", "2019-11-03", "2019-12-03", "2019-12-03")

df <- data.frame(dates=as.Date(d))

Now, I create a time-series plot:

# aggregate data
df_plot <- df %>% mutate(month = lubridate::floor_date(dates, "month")) %>% 
  group_by(month) %>% summarise(count = n())

# plot data
ggplot(aes(x = month, y = count), data = df_plot) + geom_line() +
  scale_x_date() +
  geom_vline(xintercept = as.numeric(as.Date("2019-01-30")), linetype=4)

With geom_vline(xintercept = as.numeric(as.Date("2019-01-30")), linetype=4) I can mark a certain date with a vertical line. Is there also a possibility to mark a time-range (let's say from 2019-01-30 to 2019-02-15) with a colored box or something?