What the 1918 flu has to do with our vaccine choices today

My great-grandfather died of the 1918 flu. Last year I ended up in the intensive care unit in Auckland Hospital, with bacterial pneumonia that was likely a complication of influenza or another viral infection. And as a biological anthropologist specialising in infectious disease, I’ve learned a lot about the history of epidemics and pandemics.

New Zealand’s current severe flu season has brought aspects of my experience and memory to mind. As hospitals grapple with a particularly severe flu season, it’s worth asking why some people – beyond issues of cost and access – will choose to get their flu jab, and others don’t.

Our collective memory, family history, and personal experience all shape how we think about infectious diseases, such as influenza, which can cause serious outbreaks (even pandemics). These memories influence whether we’ll get a vaccine, and the protective measures we take (or don’t) in response to a new outbreak.

Sometimes the link between memory and action can be straightforward. Perhaps a grandparent died or was seriously affected by influenza, or polio, or measles, and so you are proactive about keeping those or other vaccinations up to date.

Public health messaging often focuses on facts, but people rarely encounter those facts with a blank slate. They bring family stories, past experiences and collective memories with them. Understanding those memories may be just as important as understanding the disease itself.

When Covid arrived, many of us turned to the past for clues on what we should do. The 1918 flu was suddenly in the news again, and social media posts were full of comparisons with earlier epidemics. In our research examining New Zealand media coverage during the first two years of the pandemic, the 1918 influenza outbreak emerged as the historical event people turned to most often.

It gave New Zealanders a way of making sense of something frightening and unfamiliar. It reminded us that we weren’t the first, that other generations had also lived through lockdowns, school closures, quarantines and uncertainty, and come out the other side.

Memories can reassure us, and prompt us to act. My research found that as the pandemic evolved, references to past epidemics shifted from comforting stories about resilience to sharper warnings about what could happen if lessons from history were ignored. Memories of the devastation caused by influenza and polio became arguments for vaccination and public health action. In other words, we don’t just use the past to understand the present. We use it to imagine possible futures, and what we should do to avoid repeating recent histories.

In 2021, when Covid-19 vaccines became available in New Zealand, many looked back to collective memories of the 1913 smallpox epidemic and the 1918 flu and their impact on Māori communities. Personal memories of polio epidemics and the arrival of polio vaccines in the 1950s and 60s (often too late for some communities) also surfaced. These memories became ‘historical touchstones’ for those urging fellow Māori, and all New Zealanders, to get vaccinated against Covid.

Similarly, research with people with experience of HIV/Aids, particularly LGBT communities, showed how that memory contributed to their responses to Covid-19 – such as through greater use of protective measures like mask-wearing and social distancing.

At other times it might be more complicated. The memories that shape people’s decisions aren’t always the ones public health officials expect. Research on the 2022 polio outbreaks in New York and London found that public health officials drew on the 20th century history of devastating polio epidemics and the successful vaccination campaigns that drove the poliovirus close to global eradication.

However, many people looked back to their more recent experiences of the Covid-19 pandemic, and the trust or mistrust it generated. Those memories played a bigger role in informing their response to messages about vaccinating their children against polio.

In looking at the current research in this area, I’ve found a recurring theme and message: memories of past public health crises – including how officials and people in general responded to them – will shape how future crises are perceived and how we respond to them.

This year’s severe flu season is a chance to reflect on our personal and collective memories of past outbreaks and how they continue to influence our choices and affect our health.