On October 21, 5,743 people tested positive for the coronavirus in the country. That was the highest number of reported cases on a single day ever since Nepal reported its first Covid-19 case in the third week of January last year.

Health facilities designated for the treatment of coronavirus cases were being overwhelmed with patients as there were insufficient beds in intensive care units and ventilators. Seriously ill patients were dying before reaching hospitals.

The number of positive cases had been gradually increasing till then and the government, at a loss about how to control the pandemic with hospitals unable to cope, had even decided to stop free testing, a decision the Supreme Court eventually overturned, as well as free treatment for the general public. Contact tracing was halted altogether as a result of which testing declined.

But instead of rising, the number of cases gradually went down.

“We all know that the number of tests has declined but it is not only the reason for the drop in the numbers of positive cases,” said Dr Basudev Pandey, who served as director at the Epidemiology and Disease Control Division till about a month back.

On Saturday, Nepal reported only 99 positive cases—the first time the number of new cases recorded came to double digits since July 18—from 2,794 tests conducted in the last 24 hours.

The Ministry of Health and Population also reported zero deaths in the preceding 24 hours on Saturday. It was the third time in 10 days that zero fatalities were reported.

On Sunday, the number of positive cases went up to 119, and three died of Covid-19-related complications, but since October last year, the numbers have been going down dramatically.

Experts are at a loss to explain why.

Although studies have not been carried out, they have their hypotheses.

“Detailed and scientific study is yet to be carried out but existing variants of the virus might have become weaker than in the past,” Pandey told the Post.

He also did not rule out the chance that more people might have already been infected with the coronavirus and have antibodies against new infections.

But a large scale seroprevalence survey has not been carried out in the country of late.

The Ministry of Health and Population had carried out a seroprevalence study throughout the country which showed that around 13 percent of the total population—or one in eight persons—had been infected before September. It, however, did not publish the results.

The ministry had decided to carry out another seroprevalence study with a larger sample size. But that has not happened.

A large scale seroprevalence study carried out in India’s capital New Delhi found that 56 percent of the population had developed coronavirus antibodies.

“Had the authorities carried out such a study in our country, we could have better knowledge about the immunity level in the general public,” Dr Anup Subedee, an infectious disease expert, told the Post. “If a large number of people have already got infected with the coronavirus, daily infection declines.”

In India, with a population of 1.4 billion, too the number of coronavirus cases has declined dramatically since September when the daily infections hovered around 100,000 but now stand at 10,000.

The climate, strict implementation of the rule that people must wear masks in public places, prevalence of other diseases that could have increased immunity and a young population have been given as possible reasons.

According to experts, it may take several months for the virus to infect five percent of the population from a few cases, but when it infects more than 20 percent of the population, it does not take more time to spread in the society.

“As highly contagious viruses like the coronavirus spread exponentially, it takes just a few weeks to spread in wider communities when the infection rate is over 20 percent,” said Subedee.

But without testing or a seroprevalence study, there is no way of knowing.

“If we carry out more tests, the number of new cases will definitely increase,” Dr Binjwala Shrestha, assistant professor at the Institute of Medicine, told the Post.

But when the government, following the Supreme Court ruling, decided to resume free testing, it tested only symptomatic cases. As a result, the number of tests declined.

A study carried out by the Nepal Health Research Council has shown that 66 percent of the total cases of coronavirus are asymptomatic and doctors say that those asymptomatic people could act as superspreaders.

From a high of 22 percent in October, the positivity rate has been around 7 percent since the start of January because those getting tested are healthy people.

“At present besides those seriously ailing, only healthy people have been seeking polymerase chain reaction tests as they need them to go abroad,” said Shrestha.

Shrestha, however, agrees that the infection rate has declined, as evident from the fact that caseload in hospitals has been down compared to the September-October level, when new infections were at peak.

Authorities had feared that during Dashain, Tihar and Chhath festivals, cases could surge.

Political rallies have been increasing since Prime Minister KP Sharma Oli dissolved the House of Representatives on December 2o. Social distancing is not being followed strictly with lax implementation of face mask rules. Schools and colleges have resumed in-person classes and daily life has more or less returned to normal like in the pre-pandemic days. These conditions make it conducive for the spread of the virus. But the fears of the spread of the virus seem to have been unfounded.

According to experts, viruses naturally become weak over time, which could be another reason behind the declining number of new cases.

“Virus keeps evolving regularly and mutation happens,” Dr Sher Bahadur Pun, chief of the Clinical Research Unit at the Sukraraj Tropical and Infectious Disease Hospital, told the Post.

The number of infections might have declined due to a number of different reasons but that does not mean people and authorities should be complacent, according to experts.

“There may have been fewer new infections due to whatever causes, but we should not forget that a second wave may come soon,” said Pun. “The virus may resurge at any time.”

Several countries in Asia and Europe, which thought they had successfully stamped out the infection in the past, are again struggling to contain the spread.

Moreover, new variants of the virus have been detected. Some have been found to be not only more infectious but also more lethal.

Doctors say even if Nepal has reached the herd immunity level, despite difficulty in defining the term, the same immunity may not work in the case of new variants of the virus. Even all vaccines may not work for all the variants.

“The thing is risk has not declined, and we have not reached a stage to give up all safety measures,” said Subedee, the infectious disease expert. “Our ongoing vaccination programme is not sufficient to contain the spread of infections. We must have alternative plans for possible surge in the infection rate.”