The UN-led polio immunization campaign in the Gaza Strip is progressing, but continued fighting is making it difficult for many families to reach the vaccination centres. Louise Wateridge from UNRWA, the UN agency supporting Palestinian refugees, said nearly 87,000 children were vaccinated on Sunday, the first day of the campaign. The World Health Organization (WHO) put the number at 86,683. By Tuesday, around 156,000 under-10s in the “middle area” of the Gaza Strip should have been reached. The children will need a second dose of the vaccine in four weeks. But the spokeswoman said it was too …