Despite strides in expanding access to insecticide-treated nets and medicines to help prevent malaria in young children and pregnant women, more people were getting sick with malaria, according to a new report published by the World Health Organisation (WHO).
In 2022, there were estimated 249 million malaria cases globally, exceeding the pre-pandemic level of 233 million in 2019 by 16 million cases. In addition to the disruptions caused by COVID-19, the global malaria response has faced a growing number of threats, such as drug and insecticide resistance, humanitarian crises, resource constraints, climate change impacts and delays in programme implementation particularly in countries with a high burden of the disease.
The 2023 World malaria report delves into the nexus between climate change and malaria. Changes in temperature, humidity and rainfall can influence the behaviour and survival of the malaria-carrying Anopheles mosquito. Extreme weather events, such as heatwaves and flooding, can also directly impact transmission and disease burden. Catastrophic flooding in Pakistan in 2022, for example, led to a five-fold increase in malaria cases in the country.
“The changing climate poses a substantial risk to progress against malaria, particularly in vulnerable regions. Sustainable and resilient malaria responses are needed now more than ever, coupled with urgent actions to slow the pace of global warming and reduce its effects,” said Dr Tedros Adhanom Ghebreyesus, WHO Director-General.
Climate variability is expected to have indirect effects on malaria trends through, for example, reduced access to essential malaria services and disruptions to the supply chain of insecticide-treated nets, medicines and vaccines. Population displacement due to climate-induced factors may also lead to increased malaria as individuals without immunity migrate to endemic areas.
Data on the long-term impact of climate change on malaria transmission is sparse. However, the direction and magnitude of any impacts are likely to vary across social and ecological systems, both within and between countries.
Trends in the global malaria burden and response
The COVID-19 pandemic significantly disrupted malaria services, leading to a surge in both incidence and mortality rates, exacerbating already stalled progress against the disease.
Globally there were an additional five million malaria cases in 2022 over the previous year and five countries bore the brunt of these increases. Pakistan saw the largest increase, with about 2.6 million cases in 2022 compared to 500 000 in 2021. Significant increases were also observed in Ethiopia, Nigeria, Papua New Guinea and Uganda.
Meanwhile, in the 11 countries that carry the highest burden of malaria, rates of new infections and deaths have levelled off following an initial upsurge during the first year of the pandemic. These countries, supported through the WHO “High burden to high impact” approach, saw an estimated 167 million malaria cases and 426 000 deaths in 2022. In view of current trends, progress towards critical 2025 milestones of the WHO global malaria strategy is off track by a wide margin.
“It is crucial to recognize the multitude of threats that impede our response efforts. Climate variability poses a substantial risk, but we must also contend with challenges such as limited healthcare access, ongoing conflicts and emergencies, the lingering effects of COVID-19 on service delivery, inadequate funding and uneven implementation of our core malaria interventions,” said Dr Matshidiso Moeti, WHO Regional Director for Africa. “To forge ahead toward a malaria-free future, we need a concerted effort to tackle these diverse threats that fosters innovation, resource mobilisation and collaborative strategies.”
Grounds for optimism
The report also cites achievements such as the phased roll-out of the first WHO-recommended malaria vaccine, RTS,S/AS01, in three African countries. A rigorous evaluation has shown a substantial reduction in severe malaria and a 13% drop in early childhood deaths from all causes in the areas where the vaccine has been administered compared with areas where the vaccine was not introduced. This substantial reduction in illness and death is on top of what is being achieved in these areas where nets, indoor spraying with insecticides and other child health interventions have already been introduced.
In October 2023, WHO recommended a second safe and effective malaria vaccine, R21/Matrix-M. The availability of two malaria vaccines is expected to increase supply and make broad-scale deployment across Africa possible.
There has also been progress toward malaria elimination in many countries with a low burden of the disease. In 2022, 34 countries reported fewer than 1000 cases of malaria compared to just 13 countries in 2000. This year alone, three more countries were certified by WHO as malaria-free – Azerbaijan, Belize and Tajikistan – and several others are on track to eliminate the disease in the coming year.
What is needed now
A substantial pivot in the fight against malaria is needed, with increased resourcing, strengthened political commitment, data-driven strategies and innovative tools. Innovation should focus on the development of more efficient, effective and affordable products.
The added threat of climate change calls for sustainable and resilient malaria responses that align with efforts to reduce the effects of climate change. Whole-of-society engagement is crucial to build integrated approaches.
Dr Michael Charles Adekunle, CEO of the RBM Partnership to End Malaria, said: “This report should be a stark warning to world leaders that we must do more to address malaria now. Key milestones that were targeted for 2020 have still not been reached owing to many variables such as COVID-19, political uncertainty and inadequate funding. WHO has made it clear that the world is a long way from being malaria-free.
“The effects of climate change and extreme weather events are already being felt and new places are seeing malaria cases spike, for example they rose sharply in Pakistan in the wake of floods. Every year we wait will make elimination that much harder, as climate change accelerates and adds to the pressures we are already facing as a result of strained resources and rising resistance to tools. Ending malaria can still be achieved but only if we act and invest now.”
Joy Phumaphi, Board Chair of the RBM Partnership to End Malaria and African Leaders Malaria Alliance Executive Secretary, said: “‘We must act now to address the multiple threats we are facing in the fight against malaria. We must address the serious funding gaps, linked to the ongoing global financial crisis, through integrated and innovative financing, address the threat of drug and insecticide resistance by fast-tracking newer, highly effective next generation medicine, insecticides and mosquito nets and recognise that we cannot turn the tide against malaria if we do not take urgent action to address the increasing threat of climate change on health.”
Peter Sands, Executive Director of the Global Fund to Fight AIDS, Tuberculosis and Malaria, said: “The report accurately describes the impact of climate change on health, highlighting shifting geographies, changing seasonal patterns and extreme weather events – all aligned to make it more difficult to shrink the malaria map. Ending malaria can still be achieved if we act now. But every year we lose, the effects of climate change will make this harder.”
