Antibody testing can be used as a strategy to improve vaccine confidence: expert

Two separate surveys have found that a sizable percentage of antibody-positive healthcare workers might “prefer to defer” COVID-19 vaccination, while citizens too support the idea of COVID-19 vaccines to be first administered to individuals who are antibody-negative

While the Ministry of Health & Family Welfare has firmed up the roll-out of the COVID-19 vaccine, under the guidance of the National Expert Group on Vaccine Administration for COVID-19 (NEGVAC), there is are growing concerns that there will be a supply-demand gap.

NEGVAC has prioritised health care workers (around 1 crore), frontline workers (around 2 crore) and people above age of 50 years and persons <50 years with associated comorbidities (around 26 crore) for COVID-19 vaccination in Phase 1.

However, there is a growing sense among healthcare workers, especially those who have already recovered from COVID-19 and are currently antibody positive, that they would prefer to defer the COVID-19 vaccination, as they already have immunity.

One such COVID-19 survivor, Chennai-based Dr Abdul Ghafur, who is a consultant in infectious diseases at Apollo Hospital, conducted a survey of 1421 healthcare workers in India to find out how his fellow medicos felt about COVID-19 vaccination

According to his survey, conducted between December 8-13, when a COVID-19 vaccine is made available 45 per cent would take the vaccine, as soon as made available. (see main image)

64 per cent of the respondents prefer to have an antibody test done before the vaccination. If the antibody test is negative, 47 per cent will take the vaccine as soon as made available. If the antibody test is positive, 29 per cent will take the vaccine as soon as made available. Those who want to defer the vaccination are concerned on the side effects and the efficacy issues

Only less than half of the healthcare workers (45 per cent) are willing to receive the vaccine, as soon as a vaccine is made available. Most participants (55 per cent) will either defer the vaccination or haven’t yet decided what to do. Less than one-tenth of the respondents (7.7 per cent) stated they would never take the COVID-19 vaccine.

The data reveals significant concerns and suggests potential solutions, according to Dr Ghafur.

Health care professionals should be at the forefront of educating the public on the need for COVID-19 vaccination as they closely follow up the updates in the vaccine research and licensing process. Any concerns among them could very well percolate down to the general public, he points out.

In his survey, the reasons cited by most respondents for the vaccine hesitancy are the concerns on the efficacy and the fear of side effects of the vaccines. He strongly urges that these concerns should be addressed.

He suggests that vaccine manufacturers and regulators around the world should be vigilant and transparent in the academic and media communications on the trial details and the licensing process. “We should be very diligent not to rush the licensing process. No doubt we need a vaccine as soon as possible, but any erosion of the trust in vaccines will adversely affect not only the COVID-19 vaccination programs but other vaccines as well.”

He also points out that a majority of the respondents (64 per cent) prefer an antibody testing before the vaccination. Those who are antibody-positive, as expected, are more likely to defer the vaccination.

To his mind, this decision is acceptable and scientific as he feels that “those who are antibody-positive can defer the vaccination until their antibody-negative vulnerable colleagues receive their shots.”

This might make sense considering that we don’t have enough doses to inoculate the whole public in a brief period. Those who prefer to defer now can take the vaccine at a later stage, points out Dr Ghafur referring to a recently published mathematical modelling (https://www.medrxiv.org/content/10.1101/2020.09.08.20190629v2) by a team of researchers in the US which confirms the usefulness of this strategy.

This modelling predicted that preferentially vaccinating seronegative individuals yielded large additional reductions in cumulative incidence and mortality in locations with higher COVID-19 seroprevalence and modest reductions in locations with low seroprevalence.

Dr Ghafur also points out, “It is surprising to observe that, those who prefer to defer the vaccination would do the same, even if the antibody were found to be negative. Only 46 per cent of the respondents were willing to receive the vaccine if the antibody is tested negative.”

Dr Ghafur suggests that the COVID-19 antibody testing could be offered to those who are hesitant to take the vaccine and while it will be nearly impossible to do prior antibody testing of the whole population, this strategy could be applied among the high seroprevalence groups and regions.

“If the antibody test is found to be negative, the individual needs to be counselled on the importance of getting vaccinated. If the antibody is found to be positive, the individual can defer the vaccination if he or she prefers but should be counselled on the need for vaccinating at a later stage,” reasons Dr Ghafur.

He reminds us that no doubt we need a vaccine as soon as possible, but any erosion of the trust in vaccines will adversely affect not only the COVID-19 vaccination programmes but other vaccines as well.

The LocalCircles survey

Dr Ghafur’s survey was followed by another one, this one run by LocalCircles, a community social media platform, which sought to understand the collective public opinion on this topic. The survey was conducted between December 7-12, and received 9800+ responses from citizens located in 203 districts of India.

To the question, “To ensure that the most vulnerable get the COVID-19 vaccine first, should the Government as a first step get a COVID-19 antibodies test done and vaccinate only those individuals who do not have COVID-19 antibodies?”, LocalCircles received 9863 responses. 71 per cent of the citizens want the Government to administer COVID-19 vaccine first to those who test negative for COVID-19 antibodies, while making the antibody test a precursor to vaccination. Only 15 per cent voted “No”.

Several Indian cities have already reported high seroprevalence in the community. Though the overall seroprevalence in the country could be ten per cent so far; several metropolitan towns and regions have reported very high rates. As per the Indian Council of Medical Research (ICMR) seroprevalence data, 25 per cent of the Delhi population is antibody positive. A recent study found 27 per cent of the Karnataka population to be seropositive. Given the high infection rate among health care workers and other front line workers, this segment is also expected to have high seroprevalence.

The Government is likely to prioritise the vaccine such that healthcare and frontline workers, senior citizens and those with co-morbidities get it first followed by the general population. The same approach could be undertaken within these groups. “We can also request those citizens who are antibody-positive to opt-out of being in the priority list and receive their doses once the antibody-negative high-risk individuals have all been vaccinated,” said Dr Ghafur.

Dr Ghafur explained the strategy further. “Antibody testing of all the individuals before vaccination, may not be logistically feasible. Utilising the existing seroprevalence data, we can identify high seroprevalence regions and groups such as health care professionals. If necessary, we can generate additional seroprevalence data. We can conduct prior antibody testing of individuals in these high seroprevalence regions and groups, before deciding on the vaccination. The strategy may not be feasible in regions and groups where the seroprevalence is less than ten per cent.”

LocalCircles will be sharing these findings with the key Government stakeholders, so they are aware of the public opinion as they finalise the vaccine administration priorities and framework.

 Survey demographics

9800+ responses were received from citizens located in 203 districts of India. 69 per cent respondents were men while 31 per cent respondents were women. 48 per cent respondents were from tier 1, 29 per cent from tier 2 and 23 per cent respondents were from tier 3, 4 and rural districts. The survey was conducted via LocalCircles platform and all participants are validated citizens who had to be registered with LocalCircles to participate in this survey.