Coronavirus (1377) Further evidence based advice for primary care from the IPCRG iQ&A service

12 October, 2021

Dear colleagues

New evidence based advice sheets for primary care from the IPCRG [International Primary Care Respiratory Group] iQ&A service are available and summarised below, which we hope will help you in getting succinct up to date advice on:

How long will the COVID-19 vaccines provide protection from severe disease?

What are the risk factors for long-COVID-19 disease/post-COVID syndrome (PCS)?

What percentage of the population is needed to be immune to SARS-CoV-2 variants to achieve population level immunity?

This advice from the IPCRG's iQ&A service (https://www.ipcrg.org/resources/ipcrg-covid-19-and-respiratory-qa) is designed to provide usable, quickly absorbed answers on some key questions raised by our Sentinel Network. The 27 published answers available on the IPCRG website are reviewed and updated regularly. This time we would like to highlight three just published answers:

How long will the COVID-19 vaccines provide protection from severe disease?

Protection against symptomatic COVID-19 illness from current SARS-CoV-2 vaccines appears to wane after 4-6 months (JCVI 2021; PHE 2021). This is consistent with previous reports of waning of efficacy of mRNA vaccines against influenza virus (Connors et al 2021). However, protection against severe COVID-19 illness appears to remain high at least 6 months after vaccination, despite variations seen in initial data on different vaccinations. For more detail go to: https://www.ipcrg.org/resources/search-resources/how-long-will-the-covid...

What are the risk factors for long-COVID-19 disease/post-COVID syndrome (PCS)?

The identification of risk factors for long-COVID/PCS remains challenging. Long-COVID/PCS is also not limited to patients with severe acute illness. While more data is needed to better define risk factors that offer the best predictive value for ongoing symptoms, apparent risk factors include female sex, older age groups and a higher number of symptoms during acute illness. Increased levels of D-dimer or C-reactive protein or reduced lymphocyte count during acute illness may also be predictive risk factors (Yong 2021). For a full overview see the table in our answer: https://www.ipcrg.org/resources/search-resources/what-are-the-risk-facto...

What percentage of the population is needed to be immune to SARS-CoV-2 variants to achieve population level immunity?

Population immunity is calculated based on the whole population. In the short term, the target for population immunity against SARS-CoV-2 may be to minimize the risk for severe COVID-19 illness, minimize the societal impact of the virus and reduce the opportunity for the emergence of new variants of the virus. The more infectious the variant, the higher the immunity level required. Measles requires 95% of the population to have immunity, for example. While the precise level required to achieve population-level immunity is currently unknown, vaccination rates above 70% of the total population have been proposed (Raina MacIntyre et al 2021). This figure may vary depending on the population, for instance where more people have compromised immune systems due to poor nutrition. For more detail go to: https://www.ipcrg.org/resources/search-resources/what-percentage-of-the-...

The IPCRG iQ&A service answers questions from our Sentinel Network of globally based front line clinicians. If you would like to join this network and contribute to our questions, you can do so via the simple form on our iQ&A homepage.

Neil Fitch

On behalf of the IPCRG iQ&A Answer Review Group and project team

Neil Fitch

IPCRG Project Manager

HIFA profile: Neil Fitch is a Research Project Manager for the International Primary Care Respiratory Group, and is based in Belgium. Professional interests: Respiratory disease; COVID-19; Advice and information; Project management. neilfitch100 AT gmail.com