India’s Covid-19 response prompt, testing appropriate: WHO’s Soumya Swaminathan
Dr Soumya Swaminathan, chief scientist at the Geneva-based World Health Organisation (WHO) is leading the global partnerships on scientific research on a vaccine and drug therapies for the infection.
India cannot depend on rapid antibody tests of unproven quality for coronavirus disease (Covid-19) diagnosis and molecular tests remain the gold standard, says Dr Soumya Swaminathan, chief scientist at the Geneva-based World Health Organisation (WHO) who is leading the global partnerships on scientific research on a vaccine and drug therapies for the infection. In a phone interview with Sanchita Sharma, Swaminathan said India, for now, is doing enough testing, but will have to scale it up as the numbers rise. Edited excerpts:
Is India testing enough people?
Data from India shows that 4-5% people, mostly at-risk populations (symptomatics, contacts, healthworkers or people in containment zones), who have been tested in India are positive for Covid-19, compared to 30-40% in other countries. This indicates testing is appropriate to the situation, but it will have to be scaled up as numbers increase.
India has suspended rapid antibody tests because of quality issues. How reliable are rapid tests?
Quality serological tests take around six months to be developed with ample data and validation. There’s a flood of tests with unproven quality, which cannot be depended on for diagnosis.
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Molecular (polymerase chain reaction, or PCR) tests are the gold standard for diagnosis because they reveal current infection. This result is actionable, as it can be followed by isolation and treatment for the patient, and quarantine and testing for close contacts. Rapid antibody tests show past infection, and are useful as an epidemiological tool to map community infection and study Sars-Cov2 transmission.
Are high summer temperatures expected to slow Sars-CoV2 transmission?
We don’t know if temperature will have an effect. From what we know, it may reduce transmission by 10%-20%, but we can’t depend on it to stop transmission.
Only 2-8% people in affected populations have antibodies against Covid-19, indicates early data. How many does herd immunity offer protection to?
We are very far away from herd immunity. For diseases with high rates of transmission, a higher number of people need to be infected for herd immunity. This virus has an R0 of 2-3, so at least 80% people need to have antibodies against the virus for herd protection. (R0, or R-nought, is the basic reproduction ratio that gives the number of people infected by one case).
South Korea has reported reinfection or reactivation in recovered patients. Will reinfection affect global efforts to develop a vaccine against Covid-19?
There is no evidence reinfection can happen. Molecular tests often detect fragments of the virus RNA that is not viable (cannot cause infection) several days after patients have clinically recovered. Diagnostic results depend on several factors, on how samples are collected, how procedures are followed, and depending on which tests are used, can show false positives or false negatives. We need more studies of the natural history of this infection and what kind of immunity is generated by people.
CEPI (Coalition for Epidemic Preparedness Innovations) has identified several promising candidates, including some that are already in clinical and pre-clinical trials. How soon can a vaccine be ready?
Our goal is a vaccine before 18 months. Normally, it takes about a decade to develop a vaccine, but global partnerships (between health agencies, academics, donors, industry, nations and philanthropies) have helped hasten development of vaccines against emerging public health threats. A vaccine against Ebola took five years, the one against zika took less than two years. The global effort to develop a Covid-19 vaccine in less than 18 months is unprecedented and would be an amazing achievement.
How has the virus evolved? Is the new vaccine expected to offer long-term protection?
Over 10,000 viral genome sequences of Sars-Cov-2 have been shared by 70-80 countries with GISAID , which is a global initiative to share influenza data. Since the start of the pandemic, laboratories in countries across the world have generated viral genome sequence data with GISAID, which has enabled real-time progress in the research and development of vaccines and drug therapies.
Some evolution in the virus is bound to happen, but the rate of mutations is lower than the influenza viruses. Scientists have identified three different closely related lineages, which give valuable insights into the origin of the virus and epidemiological data on how it is spreading across the world.
None of the changes are on any important sites – the spike protein, polymerase or protease -- which are being targeted by potential vaccines and drug therapies. These sites have no major mutations, so an effective and long-lasting vaccine appears possible.
What is the progress on WHO’s Solidarity Trial for Covid-19 treatment? Which are the most promising therapies?
It’s too early for results. India is part of this trial, with 1,200 patients enrolled so far globally. The approvals have been obtained by the National AIDS Research Organisation in Pune, which will coordinate the study.
How do you rate India’s Covid-19 response?
India’s containment response was very prompt and robust and was rolled out very early, much before cases started rising. It’s exemplary, and the doubling rate of Covid-19 is now eight days. The challenge for India now will be to sustain the gains when the lockdown lifts and to ensure infection rates stay low across all states.
New infection rate has dropped in some states like Kerala.
Kerala has done a great job. Several things contribute to its success, such as a strong primary health system, a good panchayati raj system and local governance, high education levels and public participation. This was also evident during the containment of Nipah virus disease outbreak, when robust public health measures ensured infection did not spread to other states.
Do you think Covid-19 has ushered in a new social reality for the world?
I believe it will, at least for the next two to three years before we get a vaccine to the majority of the susceptible population. Social distancing will become the norm, which will change the way we work and socialise, with fewer conferences, events and large gatherings.
The WHO warned of a second wave of infection on Monday. How high is the threat of resurgence after lockdowns lift?
That’s really the question everyone is interested in and is impossible to predict. It depends on a number of things, and can be different in different countries. A lot depends on what steps are taken between lifting the lockdown and the steps post that, and most countries are going for a phased lifting. We see in China that it’s come down to a very low level of new infections, they still have infections. It’s important to get the infection rate down, as places like Taiwan, Hongkong, South Korea and Singapore have done. They still have new infections, but they are more localised outbreaks, which are quickly detected and contained.
Will US President Donald Trump’s freeze on funding affect WHO’s work?
The WHO will stick to its mandate and continue to support countries in implementing science-based measures to slow transmission, reverse and stop Covid-19. The 193 United Nations member-states recently pledged solidarity in the response to Covid and to support the WHO, in its global role to coordinate and give technical guidance on international health. It’s early days yet, and we hope this decision does not affect our important work too much.