Outbreaks appear to be exacerbated during the worst hotspots. Will it work

LONDON – A month ago, the epidemic seemed vague. More than 750,000 cases of coronavirus were transmitted worldwide in a single day. The infection spread throughout the United States. The rest of the world is at risk from new variables known in the United Kingdom, Brazil and South Africa.

But the last month has brought in surprisingly fast, if not partial, turnarounds. New cases have dropped globally to their half-peak, mostly in the same places where the catastrophic outbreak occurred this winter with a steady improvement.

Cases are an imperfect criterion, and unequal records and tests mask the scope for outbreaks, particularly in parts of Africa, Latin America, and South Asia. But with fewer patients appearing in hospitals in many countries with the highest rates of infection, experts believe the decline is real.

“It’s a great moment of optimism, but it’s also very delicate in many ways,” said Wafa Al-Sadr, a pathologist at Columbia University’s Mailman School of Public Health. “We’ve seen the light at the end of the tunnel, but it’s still a long tunnel.”

With so many of the world’s worst epidemics, vaccinations are beginning to take effect, creating an important opportunity to isolate the virus. Experts believe the vaccine has done little to slow most epidemics so far, but small groups of countries, mainly rich ones, plan to vaccinate the weaker groups by spring.

Positive signs come with a number of warnings and dangers.

Many countries are still struggling. Brazil is facing a serious revival against the new currency found in the country. The official length shows a decrease in new cases even though they were hospitalized in Spain longer than before. And in a number of European countries – the Czech Republic, Estonia and Slovakia – infection rates are falling.

More infectious types – or defects in social distance and other measures of control – can still bring new spikes into the infection that may precede the positive effects of vaccination. One type first seen in Britain is spreading rapidly in the United States, and it is spreading to Ireland, Portugal and Jordan.

And while most countries have seen a decline in cases in the past month, the global decline has largely been driven by massive epidemics by only six countries.

There is no reason behind the recession, and the factors may vary in different places. Public health experts in the worst-affected countries attribute the progress to increasing social immunity and wearing masks, increasing the natural immunity in groups with high rates of virus ality and current infection rates.

Each factor may not be enough on its own. For example, it is believed that the immune system is better than the level needed to prevent an epidemic. But factors can combine to slow down the spread of the virus.

Although the United States did not impose a national lockdown, voluntary changes in behavior, with little immunity in severely affected communities, could help prevent even worse outcomes after the holidays, said Caitlin Rivers, an epidemiologist at Johns Hopkins University. .

“During the winter, when things got really bad, I think people saw how bad things get in their community and make different choices,” Dr. R. “They canceled gatherings, they stayed more at home, they masked. Arrived for, and those things really help, put together, to reduce transmission. ”

Mark Mendelssohn, head of infectious disease and HIV medicine at the University of Cape Town, said there were many reasons for the decline in South Africa, but the main driver was the sharp rise in infection rates last month.

“Sometimes the virus hits the barrier, because it doesn’t infect new people, and it can no longer proceed by increasing its transmission.”

British experts attribute the decline to a strict national lockdown following the holiday season. Vaccines don’t make sense: Despite a quarter of the population being vaccinated, only early recipients had significant protection until January 10, when cases began to decline there. Those initial doses were mostly for hospitalized health care workers and elderly patients.

And there were some horrific outbreaks across the Americas, South Africa and Europe, said Dr. L. Sadre, a researcher at Columbia University. “During these many months, people have become all these occasions to mingle, mingle and travel with family and friends. I think he was probably also driving that excitement. ”

The challenge of keeping the infection down until vaccinations are effective will be significantly greater in countries with slow vaccination programs.

According to the World Health Organization, vaccinations did not begin in 1,130 countries earlier this month, and only 10 countries accounted for three-quarters of vaccine doses. Many rich countries are stockpiling doses, ordering their residents to vaccinate often enough, while poorer countries have yet to receive any.

And a finding from South Africa had little effect on the rapidly spreading variant of the AstraZeneca vaccine, another shock to countries that have considered relying on relatively cheap, easy-to-store vaccines as part of their rollout.

“We’re just starting our vaccination campaign in South Africa, and it’s going to be incredibly slow and nowhere near where we want to be right now,” said Dr. Said Mendels. “It’s a slightly different landscape for countries that have vaccines.”

Experts believe the vaccine will play a crucial role in keeping infections down, preventing hospital admissions and deaths, and reducing the likelihood of future changes if countries are able to vaccinate the majority of their population. But the next period will be serious to avoid another wave of infection.

“We have a small window of opportunity to take advantage of the declining number of new infections,” said Bruno Cincio, head of disease surveillance at the European Center for Disease Prevention and Control. “We should continue with public health measures in place and vaccinate as many people as possible.”