Opinion – Atila Iamarino: Covid’s honeymoon

As of the end of February, our number of Covid-19 cases continues to fall after the omicron peak. The number of deaths is stable, above 800 per day, on average, with the possibility of following the drop in cases, as seen in European countries with more vaccinations. It’s a sign that we may be entering the Covid honeymoon.

The term was introduced in 1988 to represent the lull following major immunization campaigns, induced by vaccines or disease, where the incidence of a disease drops for a period until it returns again. When the measles vaccine began to be distributed, many countries like Egypt, Israel and the Philippines went through a few years without new cases, until they experienced an outbreak again when the honeymoon was over.

This honeymoon happens when immunization is not enough to eliminate the virus, but it is enough to reduce its transmission. Without so many vulnerable, the incidence of the disease drops or even ends at first. But as new vulnerable ones emerge and accumulate, one new case is enough for the disease to circulate again. In the case of measles, the vulnerable are newborns. Childhood vaccination serves precisely to not leave vulnerable. Therefore, the honeymoon period can last for years or even more than a decade, depending on how many children are not vaccinated in a region.

In the case of Covid, the honeymoon can be much shorter. On the one hand, natural or vaccine immunity seems to wane in a few months. Hence the need for a booster dose, especially among the elderly, who have the most accentuated fall in immunity. This drop in immunity also happens with the flu influenza virus. Protection from the flu vaccine usually lasts for a few months, enough to get us through the winter season protected. In the case of Covid, unlike the flu, the coronavirus continues to generate variants and circulate even outside the winter. So as the immunity against Covid drops, we still find the coronavirus.

We already had a Covid honeymoon in Brazil. The explosion of cases and vaccination throughout 2021 generated so many immunized that we did not have the wave of the delta variant that hit Europe. But the omnic ended that honeymoon. Now, with the passage of this wave, we can enter another period of falling cases in which everything seems to be resolved. Another honeymoon. But in a good scenario, we will still have other waves in periods like winter, at least.

The UK has already decreed that the disease has passed. Some try to do the same here. It needs to match the virus. Until we have the absolute majority vaccinated and treatments that work as antivirals for those who get sick, we will see terrible numbers.

It may seem simple to sweep the Covid problem under the rug, as we have naturalized arboviruses such as zika, dengue and chikungunya. But the mat would need to be much higher to cover Covid. Between 2008 and 2019, we recorded around 11.6 million cases of dengue, chikungunya and zika, which resulted in 6,429 deaths — more than 90% of the deaths were caused by dengue. This period includes 2015 and 2019, the worst years on record. We recorded a comparable number of deaths from Covid, 6,246, in a week in February. Seasonal flu — an endemic disease that may not be as feared as dengue, but takes many more lives — kills less than 25,000 Brazilians a year. Covid has already surpassed that number in 2022, before the end of February. Before our honeymoon.