What does our future hold: will infections continue to dominate?

2019 saw numerous outbreaks of infectious disease from major epidemics of measles, cholera, dengue and Ebola. 2019 was a year for measles despite our belief that this disease had been controlled by childhood vaccination over the previous 40 years. In 2019 the USA experienced the greatest number of measles cases since 1992. 

In New Zealand measles reached its highest level since 1997 but the outbreak in the Democratic Republic of the Congo (DRC) and Samoa placed all other outbreaks in the shade. The DRC recorded more than 310,000 cases of the disease with more than 6,000 deaths. Poor infrastructure, rampaging attacks on health care centres and limited access to healthcare hindered efforts to stop the disease spreading.

The outbreak of measles in Samoa during the last few months of 2019 produced more than 5,600 cases of the disease and 83 deaths in a population of 200,874.  Measles has a long history in Samoa. Its first encounter came in 1894 when the disease was transported to the islands aboard a steamer from New Zealand. Some 1,000 Samoans died out of a total population of only 34,500. The majority of deaths were children aged under four years.

The Samoan experience reveals the significance of human behaviour and mobility in the spread of infectious disease. In 2019 it is thought that the infection was introduced by an infected person on a flight from Auckland. This allied to a young Samoan child dying from the incorrect preparation of the MMR vaccine saw anti-vaccination groups demonstrate against vaccination causing the Samoan Government to suspend the vaccination program for 10 months. By mid- November measles had reached such a peak that the Government declared a state of emergency, ordering the closure of all schools, cancelling all Xmas public gatherings and re-introducing compulsory vaccination programs.

So what does our future hold and just how vulnerable are we? Well, barely a year goes by without a new viral infection appearing or an older one re-emerging. The new coronavirus currently emerging in China is a case in point.  Will we ever eliminate infectious disease? It remains doubtful. The only success we can look back on is smallpox while a raft of others such as polio and childhood infections remain loosely controlled.

The problem we face is that we continue to underestimate the significance of our biophysical environment and the microbial world and simply place our reliance on anti-bacterial and anti-viral drugs and vaccines to keep us free of infectious disease. Our battle against infectious disease will continue for many decades and at the moment winning this battle seems well beyond us.