Antiviral drug can cut risk of long COVID, death, says US research

Two simultaneously published studies from the US and UK have reinforced the benefit of antivirals and vaccination in reducing risk of long COVID.

Analysing public data and existing research, the use of the antiviral Nirmatrelvir (sold as Paxlovid) was found by a US research group to reduce the likelihood of long COVID in predisposed people, such as those with underlying heart, respiratory and immune system conditions.

Long COVID is broadly defined by global health authorities as the persistence of symptoms from COVID-19 from one to three months after recovery from the initial infection.

Data suggests that between 1 in 10 people will experience the condition, which is similar to other post-viral disorders such as chronic fatigue syndrome and postural orthostatic tachycardia syndrome (POTS).

The research, overseen by clinical epidemiologist Professor Ziyad Al-Aly from Washington University in St Louis, US, studied the records of nearly 300,000, predominantly male, military service veterans with positive SARS-CoV-2 tests.

It found emergency administration of Paxlovid within five days of positive test resulted in a 26% reduction in the risk of long COVID, and in 10 of 13 symptoms associated with the condition.

These included dysrhythmia, ischemic heart disease, pulmonary embolism, deep vein thrombosis, fatigue, acute kidney disease, muscle pain and shortness of breath. There was also an almost 50% reduction in the likelihood of death.

“All hypotheses of long COVID point to SARS-CoV-2 as the initiating agent,” Al-Aly says.

“Our research reinforces such theories. It stands to reason that an antiviral drug – one that suppresses viral replication – may reduce the risk of long COVID.

“This gives me hope that antivirals may hold the key to preventing long COVID-19 [but] more research is needed to determine whether antiviral drugs other than Paxlovid are also effective at preventing long COVID.”

Meanwhile a British analysis of long COVID risk factors suggests prior vaccination has a protective effect against developing the condition.

The researchers investigated all risk factors for the condition across 860,000 COVID-19 patients. They found that susceptibility to the disease was higher among females and older people.

Significant associations with long COVID were found among smokers and overweight people, as well as those with mental health conditions, asthma and diabetes. Hospitalisation and admission to intensive care was also associated with higher risk.

But pre-infection vaccination drove risk down: people who had received a jab were only half as likely to experience long COVID.

“It was reassuring to see that people who had been vaccinated had significantly less risk – almost half the risk – of developing long Covid compared to unvaccinated participants,” says first author Professor Vassilios Vassiliou, from East Anglia University, UK.

“These findings are important because they enable us to better understand who may develop long Covid and also advocate for the benefit of vaccination.”