Efforts to increase influenza vaccination rates to prevent “collision epidemics” are hampered by limited supply as manufacturers struggle to meet demand.
Germany ordered 26 million flu shots before the European winter, with Health Minister Jens Spahn saying the country “has never had so many”. The UK government has said it is aiming to vaccinate 30 million people this year, more than double the 2019 figure.
However, manufacturers claim they have not been able to meet the increased demand in such a short time. Seqirus, one of the three largest influenza vaccine producers in the world, along with Sanofi and GlaxoSmithKline, estimated that global production only increased by 1 to 2%.
“If we get an overlap of Sars-Cov-2 [the virus responsible for Covid-19] and the flu, it could be a disaster, ”said Rebecca Jane Cox, professor of medical virology at the University of Bergen. “The question will be to what extent the northern hemisphere will be affected by the flu now.”
Cheryl Cohen, associate professor of epidemiology at the University of the Witwatersrand in South Africa, said: “The specter of colliding epidemics is a concern. If the two epidemics were to overlap, that would obviously be very worrying.
The World Health Organization has warned of the difficulties some countries face in procuring influenza vaccines as stocks run out. “Anyone who has a supplemental flu shot will let us know,” Ann Moen, the group’s influenza preparedness and response manager, told a conference last month.
The 1.5 million doses Turkey hopes to receive this year will be insufficient, according to the country’s pharmacists association. “With Covid-19, we think it takes three to four times as much,” said Erdogan Colak, chairman of the group. This claim is refuted by the Turkish government.
Concerns about the two worsening respiratory diseases – and their impact on health systems – have led governments to act quickly to launch strict influenza vaccination programs in place of what were previously voluntary campaigns and not applied.
John McCauley, director of the Global Influenza Center at London’s Crick Institute, said it “would be remiss” if governments did not increase flu shots this year. The flu vaccine had prevented 15 to 52% of cases in the UK over the past five years, according to University research from Oxford. The wide range is due to the fact that in some years the vaccine is less well suited to circulating strains, which constantly mutate.
According to the WHO, up to 650,000 people die from the flu each year worldwide, compared to more than a million for Covid-19 so far this year.
Last year, before the coronavirus increased demand for influenza vaccines, Seqirus estimated that 650 million doses of the vaccine would be purchased by governments and health agencies in 2020, at a cost of $ 5 billion. dollars.
After the Australian government called on more of its population to get vaccinated against the flu, vaccine imports hit a record high of 18 million doses, compared to an average of 8 million doses from 2012 to 2017.
But as demand increases, supply has increased only marginally. “Manufacturers can extend their campaign to a point, but at this short notice there is only so much we can do,” said Beverly Taylor, head of influenza scientific affairs at Seqirus. Companies would normally need 12-18 months’ notice for any scaling up of large-scale manufacturing.
“Some governments offered things before the supply was sufficient. They should have checked first, ”she added.
GSK said it “is examining all opportunities to produce and distribute more doses of influenza vaccine for 2020 and years to come, but expects demand to continue to exceed manufacturing capacity.” He said it was “very difficult to quickly adjust manufacturing capacity to meet changes in demand.”
Experts also noted that influenza levels have been exceptionally low so far this year in the southern hemisphere – which normally peaks from June to August. The same trend has been observed in other serious respiratory diseases, such as pneumococcus, rotavirus and respiratory syncytial virus.
Professor Cohen attributed this “unprecedented reduction” in influenza cases to measures adopted to contain the coronavirus, including the use of masks, hand washing and limits on mass gatherings. And for diseases such as the flu and RSV, in which children are responsible for most of the spread, school closures have reportedly played a significant role.
“It makes you wonder if masks and social distancing might help in the future,” McCauley noted.
The relative absence of influenza, however, posed some challenges. On the one hand, scientists like Mr. McCauley spend months every year analyzing new strains of influenza to tailor vaccine production for the following year. Without a lot of flu circulating, it’s unclear whether new mutations will be detected, which means vaccines from 2021 may be less effective.
And some see the lack of flu so far this year as a worrying sign of what may be to come. “Could a lack of immunity this year increase the scale of the epidemic next time?” Asked Professor Cohen.
Influenza experts agreed the priority was to increase production and ensure that the public actually took vaccines already purchased. In Germany, for example, up to 8 million unused doses of influenza vaccine are destroyed each year.
Additional reporting by Guy Chazan in Berlin and Laura Pitel in Ankara