Is the antibody testing for COVID-19 in the general population a useful diagnostic tool?

Error message

• Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent in drupal_environment_initialize() (line 695 of /home/rprlib/prod72/www/includes/bootstrap.inc).
• Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent in drupal_environment_initialize() (line 696 of /home/rprlib/prod72/www/includes/bootstrap.inc).
• Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent in drupal_environment_initialize() (line 697 of /home/rprlib/prod72/www/includes/bootstrap.inc).
• Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent in drupal_environment_initialize() (line 700 of /home/rprlib/prod72/www/includes/bootstrap.inc).
• Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent in drupal_environment_initialize() (line 702 of /home/rprlib/prod72/www/includes/bootstrap.inc).
• Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent in include_once() (line 328 of /home/rprlib/prod72/www/sites/default/settings.php).
• Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent in include_once() (line 329 of /home/rprlib/prod72/www/sites/default/settings.php).
• Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent in include_once() (line 337 of /home/rprlib/prod72/www/sites/default/settings.php).
• Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent in include_once() (line 344 of /home/rprlib/prod72/www/sites/default/settings.php).
• Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent in drupal_settings_initialize() (line 819 of /home/rprlib/prod72/www/includes/bootstrap.inc).
• Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent in drupal_settings_initialize() (line 828 of /home/rprlib/prod72/www/includes/bootstrap.inc).
• Warning: session_name(): Session name cannot be changed after headers have already been sent in drupal_settings_initialize() (line 831 of /home/rprlib/prod72/www/includes/bootstrap.inc).
• Deprecated function: Return type of DatabaseStatementBase::execute($args = [], $options = []) should either be compatible with PDOStatement::execute(?array $params = null): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in require_once() (line 2244 of /home/rprlib/prod72/www/includes/database/database.inc).
• Deprecated function: Return type of DatabaseStatementEmpty::current() should either be compatible with Iterator::current(): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in require_once() (line 2346 of /home/rprlib/prod72/www/includes/database/database.inc).
• Deprecated function: Return type of DatabaseStatementEmpty::next() should either be compatible with Iterator::next(): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in require_once() (line 2346 of /home/rprlib/prod72/www/includes/database/database.inc).
• Deprecated function: Return type of DatabaseStatementEmpty::key() should either be compatible with Iterator::key(): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in require_once() (line 2346 of /home/rprlib/prod72/www/includes/database/database.inc).
• Deprecated function: Return type of DatabaseStatementEmpty::valid() should either be compatible with Iterator::valid(): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in require_once() (line 2346 of /home/rprlib/prod72/www/includes/database/database.inc).
• Deprecated function: Return type of DatabaseStatementEmpty::rewind() should either be compatible with Iterator::rewind(): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in require_once() (line 2346 of /home/rprlib/prod72/www/includes/database/database.inc).