Covid-19 reader: 18 February

What impact will Omicron have on long Covid?

The Lancet Voice, podcast

According to the Office for National Statistics, an estimated 1.3 million – 2% of the population – were reporting long Covid as of the beginning of January. For this study, long Covid is defined as symptoms persisting for more than four weeks after the first suspected infection that were not explained by something else. The most common symptoms are fatigue, shortness of breath and muscle or joint pain.

According to Long Covid: the NHS plan for 2021/22, Covid actually falls into three phases. With acute Covid, people typically show symptoms for up to four weeks. Where symptoms continue longer than four weeks and up to 12 weeks, it is referred to as ongoing symptomatic Covid-19. And then from 12 weeks onwards, it is known as post Covid-19 syndrome, where the symptoms cannot be explained by an alternative diagnosis. Guidance from the National Institute for Health and Care Excellence states that ‘long Covid’ includes both ongoing symptomatic Covid and post-Covid syndrome.

This is broadly comparable with a World Health Organization definition. Speaking to the latest The Lancet Voice podcast, Claire Steves, clinical senior lecturer at King’s College London and a consultant geriatrician at Guy’s and St Thomas’ NHS Foundation Trust explained that having an agreed definition was vital for research, making it easier to set up trials and recruit patients. And further research will be important in coming to grips with the condition

Dr Steves said that long Covid was already having a huge impact on people’s lives and healthcare services. And she added that it was an issue across the world, although it was more talked about in high income countries.

However, she said the future trajectory of long Covid was unclear, particularly after the emergence of the Omicron variant, which had infected substantially more people in most countries than previous waves. Would this lead to a parallel increase in long Covid? Or because of its ‘milder’ impact, would long Covid not be such an issue?

‘We can’t predict how Omicron will fare in terms of long Covid,’ she said. ‘Omicron appears to affect the lower respiratory tract differently to Delta. So that might have a significant impact on who goes to intensive care. And the ventilatory burden and respiratory disease appears to be different with Omicron.’

However, breathlessness is only one aspect of long Covid symptoms. ‘So, we can’t say that, because it doesn’t affect the lungs so much, Omicron won’t lead to long Covid,’ she added. ’It might not lead to that particular characteristic of long Covid or to such respiratory damage, but what about neurological changes such as brain fog and long-term fatigue? The mechanisms behind these might not be respiratory as much immunological or neurological.’

Vaccines offer protection against long Covid

UK Health Security Agency, review

Most people take the benefits of vaccines for granted in terms of protecting against Covid-19 infection and reducing the chances of hospitalisation and death. But a review published this week has now added a reduced likelihood of developing long Covid to the list of advantages.

The UK Health Security Agency (UKHSA) carried out a rapid evidence review looking at the effects of vaccination against long Covid or post-Covid symptoms, taking into account 15 studies from the UK and around the globe.

Eight of the studies looked at the effect of vaccinations given before infection. Most of these found that vaccinated people were less likely to develop symptoms of long Covid following infection compared with unvaccinated people. This was the case both in the short term (four weeks) and long term (six months post infection).

For example, if you had two doses of the Pfizer, AstraZeneca or Moderna vaccines – or a single dose of the Janssen vaccine – you were half as likely to develop long Covid symptoms as someone with a single dose or no vaccine at all.

The remaining studies looked at the impact of vaccination on those already with long Covid. Four studies compared symptoms before and after vaccination, with three suggesting vaccination was followed by an improvement in symptoms.

Three further studies compared the impact of vaccination on symptoms compared with cases where people remained unvaccinated. Here again vaccines appeared to shorten the duration of post-Covid symptoms. One study suggested that vaccination soon after diagnosis could lead to better outcomes, while another found that a greater proportion of vaccinated participants improved compared to unvaccinated ones.

Mary Ramsay, head of immunisation at UKHSA, said the studies added to the potential benefits of receiving a full course of the Covid vaccination. ‘Vaccination is the best way to protect yourself from serious symptoms when you get infected and may also help to reduce the longer-term impact,’ she said.

Parental choice is key to child vaccination

Joint Committee on Vaccination and Immunisation, statement

The government went to great lengths to stress that the opening up of Covid vaccinations for children aged five to 11, announced this week, was a ‘non-urgent offer’. Unlike the approach for adult vaccination – which has involved strong encouragement and saw the government come close to mandating vaccination as a condition of deployment for health and care staff – for young children, parents are being put under no pressure to decide one way or the other.

Health and social care secretary Sajid Javid (pictured) pointed out that the NHS was already offering vaccines to at-risk children and those who live with immunosuppressed people in this age group. And the government was now accepting advice from the Joint Committee on Vaccination and Immunisation (JCVI) to open up the vaccine offer to all children in this age range.

‘Children without underlying health conditions are at low risk of serious illness from Covid-19 and the priority remains for the NHS to offer vaccines and boosters to adults and vulnerable young people, as well as to catch-up with other childhood immunisation programmes,’ he said.

The JCVI acknowledged that, ‘in comparison to the rest of the population/older age groups, evidence indicates that children aged five to 11 are at the very lowest risk from Covid-19’. Rates of hospitalisation, paediatric intensive care admission and death are lower in this age group than in all older age groups. And a high level of prior infection – 85% of children in this group are believed to have had the virus by the end of January 2022 – should already give a level of natural immunity.

While the vaccine is typically well tolerated in this age group, there are some side effects such as fatigue, headache and injection site pain. In the United States, where eight million children in this age group have been vaccinated, up to 10% of children reported at least one-day absence from school post-vaccination. But severe adverse events are rare. In the US, fewer than two cases of vaccine-related myocarditis (inflamed heart muscle) were reported per million doses.

The committee said there could be benefits from vaccination, with vaccine-induced protection against severe disease expected to be good and long lasting. However, vaccination of children in this group is not expected to have an impact on the current wave of Omicron infection, with the benefits applying to potential future waves of infection.

The JCVI estimates that vaccinating one million children would prevent 98 hospitalisations due to acute Covid-19 if the next wave was more severe than the current Omicron-dominated wave. This would reduce to 17 avoided admissions in a mild wave.

The JCVI stressed that the delivery of Covid-19 vaccination for five- to 11-year-olds should not be delivered at the expense of non-Covid immunisation programmes across all ages, which has fallen behind in some areas.