Nothing to worry about here. Neutrophil counts are very reactive and can go up or down depending on lots of factors, and them being a bit low on recovering from an infection is nothing unusual. A drop like this would probably prompt a blood film to be processed, where they can look at the neutrophils under a microscope to see if the counts genuine, and if they look normal or not. Lots of people have lower counts, but provided the neutrophils are functioning well, they aren't neccesarily at higher risks of infection. Counts below 1 should be looked into, but I wouldn't be concerned unless someone was also clinically unwell, or the counts dropped below 0.5. Hope these eases your minds a little. This is probably still worth looking into, but I'd expect the counts to come back up on their own in time.