I'm analysing a dataset where children were followed-up for a year, and a swab has been done every month to find out if children were colonised by pneumococcus.

Since not all children were assessed every month there are cases were an interval-censored can be used to inform about the time for clearance of the pneumococcus.

But in other cases, it happens that I cannot say where the colonisation (Positive) starts or when did clearance happened (Neg.).

Here is an example:

Neg, No sample, Positive, No sample, No sample, Positive, No sample, Neg.

Colonisation started between the first Neg and the first Positive sample but clearance may have occurred at any point after my first positive sample. Although, I know that if all non-sampled were positive then clearance happened in the last Neg swab.

Should I use multiple imputation methods in these cases? Is there any package in R that would facilitate the analysis? Thanks in advance.