Sero surveillance: Rapid way to adapt to the new normal

Covid 19 is an ongoing global pandemic which can cause severe acute respiratory syndrome (SARS CoV 2) and be fatal. It was first detected by doctors in Wuhan province of China in December 2019.  

On January 30 this year, World Health Organization Director-General Dr Tedros Adhanom Ghebreyesus declared the outbreak a Public Health Emergency of International Concern, following a second meeting of the Emergency Committee convened under the International Health Regulations.

Later on March 11, the World Health Organization characterized Covid-19 as a pandemic. As of September 15, a total of 29,445,668 cases of coronavirus were reported across the world. So far, the virus has claimed 932, 744 lives worldwide, while 21, 279, 833 people have fully recovered.

The virus spreads mostly through nose and mouth secretions, including respiratory droplets produced during coughing, sneezing, or talking.

However, these droplets usually do not spread long via air but can reach someone standing close. Therefore, if a person is infected with Covid-19 and he sneezes without covering his face, someone standing within one metre may inhale the droplets and get infected by the virus.

Besides, people can get infected by touching a contaminated surface and then touching their eyes, nose, or mouth.

According to WHO, the airborne transmission of Covid-19 may occur in circumstances and settings which procedures or support treatments that generate aerosols are performed; i.e., endotracheal intubation, bronchoscopy, open suctioning, administration of nebulised treatment, manual ventilation before intubation, turning the patient to the prone position, disconnecting the patient from the ventilator, non-invasive positive-pressure ventilation, tracheostomy, and cardiopulmonary resuscitation.

New evidence suggests that the virus may spread through flatus, stool, urine, untreated water and semen, which makes it even more dangerous.

The only way to prevent this virus is by maintaining healthy habits, social distancing and if symptoms start to surface the patient must go for quick diagnosis and treatment. The RT-PCR test is designed to detect Covid-19. However, many poor countries are not being able to test the majority of the population due to many factors, including scarcity of testing kits.

Photo: Reuters.

Countries went into lockdown and millions of citizens were asked to stay home so that the virus did not spread. Offices and businesses were shut, which resulted in an economic crisis and recession.

Slowly, economies around the world began to revive to feed its population and prevent further collapse. Markets and business places openedadapting to the new normal to ease the life of its citizens. This is where the name of "sero surveillance" emerged.

According to the Australian National Centre for Immunisation Research and Surveillance, sero surveillance can be defined as providing estimates of antibody levels against infectious diseases and is considered the gold standard for measuring population immunity due to past infection or vaccination.

It is an important component of disease surveillance and complements notification, hospitalisation, mortality and immunisation coverage data, thus providing information regarding nation-wise herd immunity.

Sero surveillance also provides information on the proportion of the population that may have acquired immunity from Covid-19. The potential applications of the sero surveillance programme are: examining trends of immunity over time, evaluating the impact of vaccination programmes, identifying groups at risk, informing immunisation policy, disease modelling, estimating the burden of specific VPDs.

Different countries have adopted sero surveillance as a tool to adapt to the Covid-19 pandemic. Some has taken time interval methods ,while others are doing population cluster surveillance or thinking of continuous monitoring until the pandemic ends.

Recently, health authorities in Delhi have completed collecting blood samples for the second round of serological surveillance. The survey will indicate the percentage of the city's population that has developed antibodies against the virus since the first such survey, which was held between June 27 and July 10.

During the first survey, it was found that 22.6 percent of the population had developed the antibodies against the virus. After the second round, the authorities are expecting antibodies in at least 40 percent of the population. This is a need-based survey to assess the necessity of vaccination. Also, the authorities are currently preparing for nationwide sero surveillance.

Several studies of contact tracing found that children are less likely to contract the virus compared to adults. For example in New York and Israel, where all household members took the RT-PCR, children were infected at around half the percentages of adults within the same household, regardless of symptoms.

A household contact study from The Netherlands using serology along with RT-PCR showed similar findings and indicated that children have been protected from transmission by school closures, which proves that a significant proportion of community transmission did not occur before the closing of schools, after which a blast of transmission was within home, from which children weren't guarded.

Further data from Iceland where schools remained opened and The Netherlands have confirmed small levels of child-to-child or child-to-adult transmission.

Again, sero surveillance can lead us to determine the cases of re-infection and chronic infection via Ig A, Ig M, Ig G, which is a possibility we cannot ignore.

As new evidence emerges and newer demands rise, a Covid-19 policy should be formulated to adapt to the new normal since the long-term effect of the virus is almost certain. We must try to minimise the effect by a rotation of our workers or, introducing new shifts of work or explore the possibility of home work for some workers permanently.

This will open a new dimension of economy and lifestyle. In an era where there are more mobile phones than people in the world and 59 percent of the world population has access to the internet, we need to use our infrastructure and resources properly.

We cannot drive our population in the wrong path like stopping educational institutions in the name of protecting our young generation.

Both Rt-PCR and antibody testing must be done simultaneously to make our country's policies sharp in adapting to the new normal. The educational institutions should be opened but health precautions should be maintained strictly.

Workers should work from home where applicable, and work in shifts by minimizing our holidays if required.

We can not stay at home to protect ourselves from Covid-19  and it is not an option for a majority ofus. The Covid 19 may go away spontaneously or go with the invention of effective treatment, until then "TEST, TEST, TEST' is our only option.

The author is a medical officer of DGHS.